diff --git a/bin/erlang-petstore-proper.sh b/bin/erlang-petstore-proper.sh
new file mode 100755
index 0000000000..cb6c9b27f0
--- /dev/null
+++ b/bin/erlang-petstore-proper.sh
@@ -0,0 +1,32 @@
+#!/bin/sh
+
+SCRIPT="$0"
+echo "# START SCRIPT: $SCRIPT"
+
+while [ -h "$SCRIPT" ] ; do
+  ls=`ls -ld "$SCRIPT"`
+  link=`expr "$ls" : '.*-> \(.*\)$'`
+  if expr "$link" : '/.*' > /dev/null; then
+    SCRIPT="$link"
+  else
+    SCRIPT=`dirname "$SCRIPT"`/"$link"
+  fi
+done
+
+if [ ! -d "${APP_DIR}" ]; then
+  APP_DIR=`dirname "$SCRIPT"`/..
+  APP_DIR=`cd "${APP_DIR}"; pwd`
+fi
+
+executable="./modules/openapi-generator-cli/target/openapi-generator-cli.jar"
+
+if [ ! -f "$executable" ]
+then
+  mvn -B clean package
+fi
+
+# if you've executed sbt assembly previously it will use that instead.
+export JAVA_OPTS="${JAVA_OPTS} -XX:MaxPermSize=256M -Xmx1024M -DloggerPath=conf/log4j.properties"
+ags="generate -t modules/openapi-generator/src/main/resources/erlang-proper -DpackageName=petstore -i modules/openapi-generator/src/test/resources/2_0/petstore.yaml -g erlang-proper -o samples/client/petstore/erlang-proper $@"
+
+java $JAVA_OPTS -jar $executable $ags
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ErlangProperCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ErlangProperCodegen.java
new file mode 100644
index 0000000000..f580ea6095
--- /dev/null
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ErlangProperCodegen.java
@@ -0,0 +1,542 @@
+/*
+ * Copyright 2018 OpenAPI-Generator Contributors (https://openapi-generator.tech)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.openapitools.codegen.languages;
+
+import com.samskivert.mustache.Mustache;
+import com.samskivert.mustache.Template;
+import io.swagger.v3.oas.models.media.ArraySchema;
+import io.swagger.v3.oas.models.media.Schema;
+import org.openapitools.codegen.*;
+import org.openapitools.codegen.utils.ModelUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.Writer;
+import java.math.BigDecimal;
+import java.util.*;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class ErlangProperCodegen extends DefaultCodegen implements CodegenConfig {
+    private static final Logger LOGGER = LoggerFactory.getLogger(ErlangProperCodegen.class);
+
+    protected String packageName = "openapi";
+    protected String packageVersion = "1.0.0";
+    protected String sourceFolder = "src";
+    protected String modelFolder = "model";
+
+    public CodegenType getTag() {
+        return CodegenType.CLIENT;
+    }
+
+    public String getName() {
+        return "erlang-proper";
+    }
+
+    public String getHelp() {
+        return "Generates an Erlang library with PropEr generators (beta).";
+    }
+
+    public ErlangProperCodegen() {
+        super();
+        outputFolder = "generated-code/erlang";
+        modelTemplateFiles.put("model.mustache", ".erl");
+        apiTemplateFiles.put("api.mustache", "_api.erl");
+        apiTemplateFiles.put("statem.mustache", "_statem.erl");
+
+        embeddedTemplateDir = templateDir = "erlang-proper";
+
+        setReservedWordsLowerCase(
+                Arrays.asList(
+                        "after", "and", "andalso", "band", "begin", "bnot", "bor", "bsl", "bsr", "bxor", "case",
+                        "catch", "cond", "div", "end", "fun", "if", "let", "not", "of", "or", "orelse", "receive",
+                        "rem", "try", "when", "xor"
+                )
+        );
+
+        instantiationTypes.clear();
+
+        typeMapping.clear();
+        typeMapping.put("enum", "binary()");
+        typeMapping.put("date", "date()");
+        typeMapping.put("datetime", "datetime()");
+        typeMapping.put("DateTime", "datetime()");
+        typeMapping.put("boolean", "boolean()");
+        typeMapping.put("string", "binary()");
+        typeMapping.put("integer", "integer()");
+        typeMapping.put("int", "integer()");
+        typeMapping.put("float", "integer()");
+        typeMapping.put("long", "integer()");
+        typeMapping.put("double", "float()");
+        typeMapping.put("array", "list()");
+        typeMapping.put("map", "map()");
+        typeMapping.put("number", "integer()");
+        typeMapping.put("bigdecimal", "float()");
+        typeMapping.put("List", "list()");
+        typeMapping.put("object", "map()");
+        typeMapping.put("file", "binary()");
+        typeMapping.put("binary", "binary()");
+        typeMapping.put("bytearray", "binary()");
+        typeMapping.put("byte", "binary()");
+        typeMapping.put("uuid", "binary()");
+        typeMapping.put("password", "binary()");
+
+        cliOptions.clear();
+        cliOptions.add(new CliOption(CodegenConstants.PACKAGE_NAME, "Erlang application name (convention: lowercase).")
+                .defaultValue(this.packageName));
+        cliOptions.add(new CliOption(CodegenConstants.PACKAGE_NAME, "Erlang application version")
+                .defaultValue(this.packageVersion));
+    }
+
+    @Override
+    public CodegenModel fromModel(String name, Schema model, Map<String, Schema> allDefinitions) {
+        CodegenModel cm = super.fromModel(name, model, allDefinitions);
+        if(ModelUtils.isArraySchema(model)) {
+            return new CodegenArrayModel(cm, (ArraySchema) model);
+        } else {
+            return cm;
+        }
+    }
+
+    @Override
+    public String getTypeDeclaration(String name) {
+        return name + ":" + name + "()";
+    }
+
+    @Override
+    public String getTypeDeclaration(Schema schema) {
+        String typeDeclaration = super.getSchemaType(schema);
+        if(ModelUtils.isArraySchema(schema)) {
+            ArraySchema arraySchema = (ArraySchema) schema;
+            String complexType = getSchemaType(arraySchema.getItems());
+
+            StringBuilder sb = new StringBuilder("list(");
+            sb.append(complexType);
+
+            return sb.append(")").toString();
+        } else if (typeMapping.containsKey(typeDeclaration)) {
+            return typeMapping.get(typeDeclaration);
+        } else {
+            return getTypeDeclaration(toModelName(snakeCase(typeDeclaration)));
+        }
+    }
+
+    @Override
+    public String getSchemaType(Schema schema) {
+        String schemaType = super.getSchemaType(schema);
+        if(ModelUtils.isArraySchema(schema)) {
+            ArraySchema arraySchema = (ArraySchema) schema;
+            String complexType = getSchemaType(arraySchema.getItems());
+
+            StringBuilder sb = new StringBuilder("list(");
+            sb.append(complexType);
+
+            Integer minItems = schema.getMinItems();
+            Integer maxItems = schema.getMaxItems();
+            if(minItems != null) sb.append(", ").append(minItems);
+            if(minItems != null && maxItems != null) sb.append(", ").append(maxItems);
+
+            return sb.append(")").toString();
+        } else if(ModelUtils.isIntegerSchema(schema)) {
+            StringBuilder sb = new StringBuilder("integer(");
+
+            BigDecimal min = schema.getMinimum();
+            BigDecimal max = schema.getMaximum();
+            if(min != null) sb.append(min);
+            if(min != null && max != null) sb.append(", ").append(max);
+
+            return sb.append(")").toString();
+        } else if(ModelUtils.isDateSchema(schema) || ModelUtils.isDateTimeSchema(schema)) {
+            return typeMapping.get(schemaType);
+        } else if(ModelUtils.isStringSchema(schema)) {
+            StringBuilder sb = new StringBuilder("binary(");
+            Integer min = schema.getMinLength();
+            Integer max = schema.getMaxLength();
+            if(min != null) sb.append(min);
+            if(min != null && max != null) sb.append(", ").append(max);
+
+            return sb.append(")").toString();
+        } else if (typeMapping.containsKey(schemaType)) {
+            return typeMapping.get(schemaType);
+        } else {
+            return getTypeDeclaration(toModelName(snakeCase(schemaType)));
+        }
+    }
+
+    @Override
+    public void processOpts() {
+        super.processOpts();
+
+        if (additionalProperties.containsKey(CodegenConstants.PACKAGE_NAME)) {
+            setPackageName((String) additionalProperties.get(CodegenConstants.PACKAGE_NAME));
+        } else {
+            setPackageName("openapi");
+        }
+
+        if (additionalProperties.containsKey(CodegenConstants.PACKAGE_VERSION)) {
+            setPackageVersion((String) additionalProperties.get(CodegenConstants.PACKAGE_VERSION));
+        } else {
+            setPackageVersion("1.0.0");
+        }
+
+        additionalProperties.put(CodegenConstants.PACKAGE_NAME, packageName);
+        additionalProperties.put(CodegenConstants.PACKAGE_VERSION, packageVersion);
+
+        additionalProperties.put("length", new Mustache.Lambda() {
+            @Override
+            public void execute(Template.Fragment fragment, Writer writer) throws IOException {
+                writer.write(length(fragment.context()));
+            }
+        });
+
+        additionalProperties.put("qsEncode", new Mustache.Lambda() {
+            @Override
+            public void execute(Template.Fragment fragment, Writer writer) throws IOException {
+                writer.write(qsEncode(fragment.context()));
+            }
+        });
+
+        modelPackage = packageName;
+        apiPackage = packageName;
+
+        supportingFiles.add(new SupportingFile("rebar.config.mustache", "", "rebar.config"));
+        supportingFiles.add(new SupportingFile("app.src.mustache", "", "src" + File.separator +
+            this.packageName + ".app.src"));
+        supportingFiles.add(new SupportingFile("utils.mustache", "", "src" + File.separator +
+            this.packageName + "_utils.erl"));
+        supportingFiles.add(new SupportingFile("gen.mustache", "", "src" + File.separator + this
+            .packageName + "_gen.erl"));
+        supportingFiles.add(new SupportingFile("include.mustache", "", "src" + File.separator +
+            this.packageName + ".hrl"));
+        supportingFiles.add(new SupportingFile("statem.hrl.mustache", "", "src" + File.separator +
+            this.packageName + "_statem.hrl"));
+        supportingFiles.add(new SupportingFile("test.mustache", "", "test" + File.separator +
+            "prop_" + this.packageName + ".erl"));
+        supportingFiles.add(new SupportingFile("README.mustache", "", "README.md"));
+    }
+
+    private String qsEncode(Object o) {
+        String r = "";
+        CodegenParameter q = (CodegenParameter) o;
+        if (q.required) {
+            if (q.isListContainer) {
+                r += "[{<<\"" + q.baseName + "\">>, X} || X <- " + q.paramName + "]";
+            } else {
+                r += "{<<\"" + q.baseName + "\">>, " + q.paramName + "}";
+            }
+        }
+        return r;
+    }
+
+    @Override
+    public String escapeReservedWord(String name) {
+        // Can't start with an underscore, as our fields need to start with an
+        // UppercaseLetter so that Go treats them as public/visible.
+
+        // Options?
+        // - MyName
+        // - AName
+        // - TheName
+        // - XName
+        // - X_Name
+        // ... or maybe a suffix?
+        // - Name_ ... think this will work.
+        if (this.reservedWordsMappings().containsKey(name)) {
+            return this.reservedWordsMappings().get(name);
+        }
+        return camelize(name) + '_';
+    }
+
+    @Override
+    public String apiFileFolder() {
+        return outputFolder + File.separator + sourceFolder + File.separator;
+    }
+
+    @Override
+    public String modelFileFolder() {
+        return outputFolder + File.separator
+            + sourceFolder + File.separator
+            + modelFolder + File.separator;
+    }
+
+    @Override
+    public String toVarName(String name) {
+        // replace - with _ e.g. created-at => created_at
+        name = sanitizeName(name.replaceAll("-", "_"));
+        // for reserved word or word starting with number, append _
+        if (isReservedWord(name))
+            name = escapeReservedWord(name);
+
+        return name;
+    }
+
+    @Override
+    public String toParamName(String name) {
+        return camelize(toVarName(name));
+    }
+
+    @Override
+    public String toArrayModelParamName(String name) {
+        if (name == null) {
+            LOGGER.warn("parameter name for array model is null. Default to 'array_model'.");
+            name = "array_model";
+        }
+
+        if (name.indexOf(":") > 0) {
+            name = name.substring(0, name.indexOf(":")) + "_array";
+        }
+
+        return toParamName(name);
+    }
+
+    @Override
+    public String toModelName(String name) {
+        return this.packageName + "_" + underscore(name.replaceAll("-", "_").replaceAll("\\.", "_"));
+    }
+
+    @Override
+    public String toApiName(String name) {
+        return this.packageName;
+    }
+
+    @Override
+    public String toModelFilename(String name) {
+        return this.packageName + "_" + underscore(name.replaceAll("\\.", "_"));
+    }
+
+    @Override
+    public String toApiFilename(String name) {
+        return toApiName(name);
+    }
+
+    @Override
+    public String toOperationId(String operationId) {
+        // method name cannot use reserved keyword, e.g. return
+        if (isReservedWord(operationId)) {
+            LOGGER.warn(operationId + " (reserved word) cannot be used as method name. Renamed to " + underscore(sanitizeName("call_" + operationId)).replaceAll("\\.", "_"));
+            operationId = "call_" + operationId;
+        }
+
+        return underscore(operationId.replaceAll("\\.", "_"));
+    }
+
+    @Override
+    public Map<String, Object> postProcessOperationsWithModels(Map<String, Object> objs, List<Object> allModels) {
+        Map<String, Object> operations = (Map<String, Object>) objs.get("operations");
+        List<CodegenOperation> os = (List<CodegenOperation>) operations.get("operation");
+        List<ExtendedCodegenOperation> newOs = new ArrayList<>();
+        Pattern pattern = Pattern.compile("\\{([^\\}]+)\\}");
+        for (CodegenOperation o : os) {
+            // force http method to lower case
+            o.httpMethod = o.httpMethod.toLowerCase(Locale.ROOT);
+
+            if (o.isListContainer) {
+                o.returnType = "[" + o.returnBaseType + "]";
+            }
+
+            Matcher matcher = pattern.matcher(o.path);
+            StringBuffer buffer = new StringBuffer();
+            while (matcher.find()) {
+                String pathTemplateName = matcher.group(1);
+                matcher.appendReplacement(buffer, "\", " + camelize(pathTemplateName) + ", \"");
+            }
+            matcher.appendTail(buffer);
+
+            ExtendedCodegenOperation eco = new ExtendedCodegenOperation(o);
+            if (buffer.length() == 0) {
+                eco.setReplacedPathName(o.path);
+            } else {
+                eco.setReplacedPathName(buffer.toString());
+            }
+            newOs.add(eco);
+        }
+        operations.put("operation", newOs);
+        return objs;
+    }
+
+    public void setPackageName(String packageName) {
+        this.packageName = packageName;
+    }
+
+    public void setPackageVersion(String packageVersion) {
+        this.packageVersion = packageVersion;
+    }
+
+    String length(Object os) {
+        int l = 1;
+        for (CodegenParameter o : ((ExtendedCodegenOperation) os).allParams) {
+            if (o.required)
+                l++;
+        }
+
+        return Integer.toString(l);
+    }
+
+    private int lengthRequired(List<CodegenParameter> allParams) {
+        int l = 0;
+        for (CodegenParameter o : allParams) {
+            if (o.required || o.isBodyParam)
+                l++;
+        }
+
+        return l;
+    }
+
+    @Override
+    public String escapeQuotationMark(String input) {
+        // remove " to avoid code injection
+        return input.replace("\"", "");
+    }
+
+    @Override
+    public String escapeUnsafeCharacters(String input) {
+        return input.replace("*/", "*_/").replace("/*", "/_*");
+    }
+
+    class CodegenArrayModel extends CodegenModel {
+        Integer minItems;
+        Integer maxItems;
+
+        public CodegenArrayModel(CodegenModel cm, ArraySchema schema) {
+            super();
+
+            // Copy all fields of CodegenModel
+            this.parent = cm.parent;
+            this.parentSchema = cm.parentSchema;
+            this.parentModel = cm.parentModel;
+            this.interfaceModels = cm.interfaceModels;
+            this.children = cm.children;
+            this.name = cm.name;
+            this.classname = cm.classname;
+            this.title = cm.title;
+            this.description = cm.description;
+            this.classVarName = cm.classVarName;
+            this.modelJson = cm.modelJson;
+            this.dataType = cm.dataType;
+            this.xmlPrefix = cm.xmlPrefix;
+            this.xmlNamespace = cm.xmlNamespace;
+            this.xmlName = cm.xmlName;
+            this.classFilename = cm.classFilename;
+            this.unescapedDescription = cm.unescapedDescription;
+            this.discriminator = cm.discriminator;
+            this.defaultValue = cm.defaultValue;
+            this.arrayModelType = cm.arrayModelType;
+            this.isAlias = cm.isAlias;
+            this.vars = cm.vars;
+            this.requiredVars = cm.requiredVars;
+            this.optionalVars = cm.optionalVars;
+            this.readOnlyVars = cm.readOnlyVars;
+            this.readWriteVars = cm.readWriteVars;
+            this.allVars = cm.allVars;
+            this.parentVars = cm.parentVars;
+            this.allowableValues = cm.allowableValues;
+            this.mandatory = cm.mandatory;
+            this.allMandatory = cm.allMandatory;
+            this.imports = cm.imports;
+            this.hasVars = cm.hasVars;
+            this.emptyVars = cm.emptyVars;
+            this.hasMoreModels = cm.hasMoreModels;
+            this.hasEnums = cm.hasEnums;
+            this.isEnum = cm.isEnum;
+            this.hasRequired = cm.hasRequired;
+            this.hasOptional = cm.hasOptional;
+            this.isArrayModel = cm.isArrayModel;
+            this.hasChildren = cm.hasChildren;
+            this.hasOnlyReadOnly = cm.hasOnlyReadOnly;
+            this.externalDocumentation = cm.externalDocumentation;
+            this.vendorExtensions = cm.vendorExtensions;
+            this.additionalPropertiesType = cm.additionalPropertiesType;
+
+            this.minItems = schema.getMinItems();
+            this.maxItems = schema.getMaxItems();
+        }
+    }
+
+    class ExtendedCodegenOperation extends CodegenOperation {
+        private String replacedPathName;
+        String arity;
+
+        ExtendedCodegenOperation(CodegenOperation o) {
+            super();
+
+            // Copy all fields of CodegenOperation
+            this.responseHeaders.addAll(o.responseHeaders);
+            this.hasAuthMethods = o.hasAuthMethods;
+            this.hasConsumes = o.hasConsumes;
+            this.hasProduces = o.hasProduces;
+            this.hasParams = o.hasParams;
+            this.hasOptionalParams = o.hasOptionalParams;
+            this.returnTypeIsPrimitive = o.returnTypeIsPrimitive;
+            this.returnSimpleType = o.returnSimpleType;
+            this.subresourceOperation = o.subresourceOperation;
+            this.isMapContainer = o.isMapContainer;
+            this.isListContainer = o.isListContainer;
+            this.isMultipart = o.isMultipart;
+            this.hasMore = o.hasMore;
+            this.isResponseBinary = o.isResponseBinary;
+            this.hasReference = o.hasReference;
+            this.isRestfulIndex = o.isRestfulIndex;
+            this.isRestfulShow = o.isRestfulShow;
+            this.isRestfulCreate = o.isRestfulCreate;
+            this.isRestfulUpdate = o.isRestfulUpdate;
+            this.isRestfulDestroy = o.isRestfulDestroy;
+            this.isRestful = o.isRestful;
+            this.path = o.path;
+            this.operationId = o.operationId;
+            this.returnType = o.returnType;
+            this.httpMethod = o.httpMethod;
+            this.returnBaseType = o.returnBaseType;
+            this.returnContainer = o.returnContainer;
+            this.summary = o.summary;
+            this.unescapedNotes = o.unescapedNotes;
+            this.notes = o.notes;
+            this.baseName = o.baseName;
+            this.defaultResponse = o.defaultResponse;
+            this.discriminator = o.discriminator;
+            this.consumes = o.consumes;
+            this.produces = o.produces;
+            this.bodyParam = o.bodyParam;
+            this.allParams = o.allParams;
+            this.arity = Integer.toString(lengthRequired(o.allParams));
+            this.bodyParams = o.bodyParams;
+            this.pathParams = o.pathParams;
+            this.queryParams = o.queryParams;
+            this.headerParams = o.headerParams;
+            this.formParams = o.formParams;
+            this.authMethods = o.authMethods;
+            this.tags = o.tags;
+            this.responses = o.responses;
+            this.imports = o.imports;
+            this.examples = o.examples;
+            this.externalDocs = o.externalDocs;
+            this.vendorExtensions = o.vendorExtensions;
+            this.nickname = o.nickname;
+            this.operationIdLowerCase = o.operationIdLowerCase;
+            this.operationIdCamelCase = o.operationIdCamelCase;
+        }
+
+        public String getReplacedPathName() {
+            return replacedPathName;
+        }
+
+        public void setReplacedPathName(String replacedPathName) {
+            this.replacedPathName = replacedPathName;
+        }
+    }
+}
diff --git a/modules/openapi-generator/src/main/resources/META-INF/services/org.openapitools.codegen.CodegenConfig b/modules/openapi-generator/src/main/resources/META-INF/services/org.openapitools.codegen.CodegenConfig
index 1659fc4169..6bd50bc8e2 100644
--- a/modules/openapi-generator/src/main/resources/META-INF/services/org.openapitools.codegen.CodegenConfig
+++ b/modules/openapi-generator/src/main/resources/META-INF/services/org.openapitools.codegen.CodegenConfig
@@ -22,6 +22,7 @@ org.openapitools.codegen.languages.EiffelClientCodegen
 org.openapitools.codegen.languages.ElixirClientCodegen
 org.openapitools.codegen.languages.ElmClientCodegen
 org.openapitools.codegen.languages.ErlangClientCodegen
+org.openapitools.codegen.languages.ErlangProperCodegen
 org.openapitools.codegen.languages.ErlangServerCodegen
 org.openapitools.codegen.languages.FlashClientCodegen
 org.openapitools.codegen.languages.FinchServerCodegen
diff --git a/modules/openapi-generator/src/main/resources/erlang-proper/README.mustache b/modules/openapi-generator/src/main/resources/erlang-proper/README.mustache
new file mode 100644
index 0000000000..cc63f05bdc
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/erlang-proper/README.mustache
@@ -0,0 +1,6 @@
+# OpenAPI client library for Erlang with Erlang QuickCheck generators
+
+## Overview
+
+An Erlang client stub and Erlang QuickCheck generators, generated by
+[OpenAPI Generator](https://openapi-generator.tech) given an OpenAPI spec.
diff --git a/modules/openapi-generator/src/main/resources/erlang-proper/api.mustache b/modules/openapi-generator/src/main/resources/erlang-proper/api.mustache
new file mode 100644
index 0000000000..7861cfbeb3
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/erlang-proper/api.mustache
@@ -0,0 +1,30 @@
+-module({{classname}}_api).
+
+-export([ {{#operations}}{{#operation}}{{^-first}}
+        , {{/-first}}{{operationId}}/{{arity}}{{/operation}}{{/operations}}
+        ]).
+
+-define(BASE_URL, "{{{basePathWithoutHost}}}").
+
+{{#operations}}
+{{#operation}}
+%% @doc {{{summary}}}
+{{^notes.isEmpty}}
+%% {{{notes}}}
+{{/notes.isEmpty}}
+-spec {{operationId}}({{#allParams}}{{#required}}{{^-first}}, {{/-first}}{{{dataType}}}{{/required}}{{/allParams}}) ->
+  {{packageName}}_utils:response().
+{{operationId}}({{#allParams}}{{#required}}{{^-first}}, {{/-first}}{{paramName}}{{/required}}{{/allParams}}) ->
+  Method      = {{httpMethod}},
+  Host        = application:get_env({{packageName}}, host, "http://localhost:8080"),
+  Path        = ["{{{replacedPathName}}}"],
+  Body        = {{^formParams.isEmpty}}{form, [{{#formParams}}{{#required}}{{^-first}}, {{/-first}}{<<"{{{baseName}}}">>, {{paramName}}{{/required}}{{/formParams}}]++{{packageName}}_utils:optional_params([{{#formParams}}{{^required}}{{^-first}}, {{/-first}}'{{{baseName}}}'{{/required}}{{/formParams}}], _OptionalParams)}{{/formParams.isEmpty}}{{#formParams.isEmpty}}{{#bodyParams.isEmpty}}[]{{/bodyParams.isEmpty}}{{^bodyParams.isEmpty}}{{#bodyParams}}{{paramName}}{{/bodyParams}}{{/bodyParams.isEmpty}}{{/formParams.isEmpty}},
+  ContentType = {{#hasConsumes}}hd([{{#consumes}}{{^-first}}, {{/-first}}"{{mediaType}}"{{/consumes}}]){{/hasConsumes}}{{^hasConsumes}}<<"text/plain">>{{/hasConsumes}},
+  {{^queryParams.isEmpty}}
+  QueryString = [{{#queryParams}}{{^-first}}, {{/-first}}<<"{{{baseName}}}=">>, {{{paramName}}}, <<"&">>{{/queryParams}}],
+  {{/queryParams.isEmpty}}
+
+  {{packageName}}_utils:request(Method, [Host, ?BASE_URL, Path{{^queryParams.isEmpty}}, <<"?">>, QueryString{{/queryParams.isEmpty}}], jsx:encode(Body), ContentType).
+
+{{/operation}}
+{{/operations}}
diff --git a/modules/openapi-generator/src/main/resources/erlang-proper/app.src.mustache b/modules/openapi-generator/src/main/resources/erlang-proper/app.src.mustache
new file mode 100644
index 0000000000..0c9bc9c2ae
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/erlang-proper/app.src.mustache
@@ -0,0 +1,21 @@
+{ application, {{packageName}}
+, [ {description, {{#appDescription}}"{{appDescription}}"{{/appDescription}}{{^appDescription}}"OpenAPI client library for EQC testing"{{/appDescription}}}
+  , {vsn, "{{#apiVersion}}{{apiVersion}}{{/apiVersion}}{{^apiVersion}}0.1.0{{/apiVersion}}"}
+  , {registered, []}
+  , { applications
+    , [ kernel
+      , stdlib
+      , ssl
+      , jsx
+      ]
+    }
+  , { env
+    , [ {host, "http://{{#host}}{{{host}}}{{/host}}{{^host}}localhost:8080{{/host}}"}
+      , {basic_auth, {"admin", "admin"}}
+      ]
+    }
+  , {modules, []}
+  , {maintainers, []}
+  , {licenses, [{{#licenseInfo}}"{{licenseInfo}}"{{/licenseInfo}}]}
+  , {links, [{{#infoUrl}}"{{infoUrl}}"{{/infoUrl}}]}
+]}.
diff --git a/modules/openapi-generator/src/main/resources/erlang-proper/gen.mustache b/modules/openapi-generator/src/main/resources/erlang-proper/gen.mustache
new file mode 100644
index 0000000000..c7da29fd14
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/erlang-proper/gen.mustache
@@ -0,0 +1,157 @@
+-module({{packageName}}_gen).
+
+-compile({no_auto_import,[date/0]}).
+
+-include_lib("proper/include/proper_common.hrl").
+
+%%==============================================================================
+%% Exports
+%%==============================================================================
+
+-export([ binary/0
+        , binary/1
+        , binary/2
+        , integer/0
+        , integer/1
+        , integer/2
+        , boolean/0
+        , list/0
+        , list/1
+        , list/2
+        , list/3
+        , map/0
+        , date/0
+        , datetime/0
+        , any/0
+        , elements/1
+        ]).
+
+-define(CHARS, [$a, $b, $c]).
+
+%%==============================================================================
+%% Generators
+%%==============================================================================
+
+binary() -> binary(10).
+
+binary(Min, Max) ->
+  ?LET( {X, N}
+      , { proper_types:elements(?CHARS)
+        , proper_types:choose(Min, Max)
+        }
+      , iolist_to_binary(lists:duplicate(N, X))
+      ).
+
+binary(N) ->
+  ?LET( X
+      , proper_types:elements(?CHARS)
+      , iolist_to_binary(lists:duplicate(N, X))
+      ).
+
+integer() -> proper_types:int().
+
+integer(0) -> proper_types:nat();
+integer(Min) ->
+  ?LET( N
+      , proper_types:nat()
+      , proper_types:choose(Min, Min + N)
+      ).
+
+integer(Min, Max) -> proper_types:choose(Min, Max).
+
+boolean() -> proper_types:bool().
+
+list() -> list(any()).
+
+list(Type) -> proper_types:list(Type).
+
+list(Type, Min) ->
+  ?LET( N
+      , integer(0)
+      , ?LET(X, list(Type, Min, Min + N), X)
+      ).
+
+list(Type, Min, Max) when Min =< Max ->
+  ?LET( {X, Y}
+      , { proper_types:vector(Min, Type)
+        , proper_types:resize(Max - Min, proper_types:list(Type))
+        }
+      , X ++ Y
+      ).
+
+map() -> proper_types:map(any(), any()).
+
+date() ->
+  ?LET( X
+      , ?SUCHTHAT( X
+                 , { year()
+                   , proper_types:choose(1, 12)
+                   , proper_types:choose(1, 31)
+                   }
+                 , calendar:valid_date(X)
+                 )
+      , begin
+          {Year, Month, Day} = X,
+          YearBin  = num_binary_format(Year, "4"),
+          MonthBin = num_binary_format(Month, "2"),
+          DayBin   = num_binary_format(Day, "2"),
+          <<YearBin/binary, "-", MonthBin/binary, "-", DayBin/binary>>
+        end
+      ).
+
+datetime() ->
+  Date = date(),
+  Hour = hour(),
+  ?LET( X
+      , {Date, Hour}
+      , begin
+          {D, H} = X,
+          <<D/binary, "T", H/binary, "+0000">>
+        end
+      ).
+
+any() ->
+  Any = [ binary()
+        , integer()
+        , boolean()
+        %% We don't include lists and maps to avoid huge values
+        %% , list()
+        %% , map()
+        , date()
+        , datetime()
+        ],
+  proper_types:oneof(Any).
+
+elements(Items) ->
+  proper_types:elements(Items).
+
+%%==============================================================================
+%% Internal
+%%==============================================================================
+
+year() ->
+  ?LET( X
+      , proper_types:nat()
+      , 1970 + X
+      ).
+
+hour() ->
+  ?LET( X
+      , { proper_types:choose(0, 23)
+        , proper_types:choose(0, 59)
+        , proper_types:choose(0, 59)
+        , proper_types:choose(0, 999)
+        }
+      , begin
+          {Hours, Mins, Secs, Millis} = X,
+          HoursBin  = num_binary_format(Hours, "2"),
+          MinsBin   = num_binary_format(Mins, "2"),
+          SecsBin   = num_binary_format(Secs, "2"),
+          MillisBin = num_binary_format(Millis, "3"),
+          <<HoursBin/binary, ":", MinsBin/binary, ":",
+            SecsBin/binary, ".", MillisBin/binary>>
+        end
+      ).
+
+num_binary_format(X, N) ->
+  list_to_binary(io_lib:format("~" ++ N ++ "..0B", [X])).
diff --git a/modules/openapi-generator/src/main/resources/erlang-proper/include.mustache b/modules/openapi-generator/src/main/resources/erlang-proper/include.mustache
new file mode 100644
index 0000000000..ee07f9f5c3
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/erlang-proper/include.mustache
@@ -0,0 +1,24 @@
+-compile({no_auto_import,[date/0]}).
+
+-import( {{packageName}}_gen
+       , [ binary/0
+         , binary/1
+         , binary/2
+         , integer/0
+         , integer/1
+         , integer/2
+         , boolean/0
+         , list/0
+         , list/1
+         , list/2
+         , list/3
+         , map/0
+         , date/0
+         , datetime/0
+         , any/0
+         , elements/1
+         ]
+       ).
+
+-type date()     :: calendar:date().
+-type datetime() :: calendar:datetime().
diff --git a/modules/openapi-generator/src/main/resources/erlang-proper/model.mustache b/modules/openapi-generator/src/main/resources/erlang-proper/model.mustache
new file mode 100644
index 0000000000..5e4024ed8d
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/erlang-proper/model.mustache
@@ -0,0 +1,26 @@
+{{#models}}
+{{#model}}
+-module({{classname}}).
+
+-include("{{packageName}}.hrl").
+
+-export([{{classname}}/0]).
+
+-export_type([{{classname}}/0]).
+
+-type {{classname}}() ::{{#isEnum}}
+  binary().{{/isEnum}}{{^isEnum}}{{#isArrayModel}}
+  list({{arrayModelType}}).{{/isArrayModel}}{{^isArrayModel}}
+  [ {{#vars}}{{^-first}}
+  | {{/-first}}{'{{name}}', {{dataType}} }{{/vars}}
+  ].{{/isArrayModel}}{{/isEnum}}
+
+{{classname}}() ->{{#isEnum}}
+  elements([{{#allowableValues.values}}{{^-first}}, {{/-first}}<<"{{.}}">>{{/allowableValues.values}}]).
+  {{/isEnum}}{{#isArrayModel}}
+  list({{arrayModelType}}{{#minItems}}, {{minItems}}{{#maxItems}}, {{maxItems}}{{/maxItems}}{{/minItems}}).{{/isArrayModel}}{{^isEnum}}{{^isArrayModel}}
+  [ {{#vars}}{{^-first}}
+  , {{/-first}}{'{{baseName}}', {{#isString}}{{#isEnum}}elements([{{#allowableValues.values}}{{^-first}}, {{/-first}}<<"{{.}}">>{{/allowableValues.values}}]){{/isEnum}}{{^isEnum}}binary({{#minLength}}{{minLength}}{{#maxLength}}, {{maxLength}}{{/maxLength}}{{/minLength}}){{/isEnum}}{{/isString}}{{^isString}}{{baseType}}{{/isString}} }{{/vars}}
+  ].{{/isArrayModel}}{{/isEnum}}
+{{/model}}
+{{/models}}
diff --git a/modules/openapi-generator/src/main/resources/erlang-proper/rebar.config.mustache b/modules/openapi-generator/src/main/resources/erlang-proper/rebar.config.mustache
new file mode 100644
index 0000000000..4a1593adca
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/erlang-proper/rebar.config.mustache
@@ -0,0 +1,7 @@
+{erl_opts, [debug_info, warnings_as_errors]}.
+
+{deps, [{jsx, "2.9.0"}, {proper, "1.3.0"}]}.
+
+{shell, [{apps, [{{packageName}}]}]}.
+
+{plugins, [rebar3_proper]}.
diff --git a/modules/openapi-generator/src/main/resources/erlang-proper/statem.hrl.mustache b/modules/openapi-generator/src/main/resources/erlang-proper/statem.hrl.mustache
new file mode 100644
index 0000000000..7b4dd931aa
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/erlang-proper/statem.hrl.mustache
@@ -0,0 +1,25 @@
+%%==============================================================================
+%% Setup
+%%==============================================================================
+
+setup() -> ok.
+
+%%==============================================================================
+%% Cleanup
+%%==============================================================================
+
+cleanup() -> ok.
+
+%%==============================================================================
+%% Initial State
+%%==============================================================================
+
+initial_state() -> #{}.
+
+%%==============================================================================
+%% State transitions callbacks
+%%
+%% operation_pre(State) -> true.
+%% operation_next(State, Result, Args) -> State.
+%% operation_post(State, Args, Result) -> true.
+%%==============================================================================
diff --git a/modules/openapi-generator/src/main/resources/erlang-proper/statem.mustache b/modules/openapi-generator/src/main/resources/erlang-proper/statem.mustache
new file mode 100644
index 0000000000..98ebdf1c54
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/erlang-proper/statem.mustache
@@ -0,0 +1,105 @@
+-module({{classname}}_statem).
+
+-behaviour(proper_statem).
+
+-include("{{packageName}}.hrl").
+-include_lib("proper/include/proper_common.hrl").
+-include_lib("stdlib/include/assert.hrl").
+
+-compile(export_all).
+-compile(nowarn_export_all).
+
+%%==============================================================================
+%% PropEr callbacks
+%%==============================================================================
+
+command(State) ->
+  Funs0 = [ {F, list_to_atom(atom_to_list(F) ++ "_args")}
+            || {F, _} <- ?MODULE:module_info(exports)
+          ],
+
+  Funs1 = [ X || {_, FArgs} = X <- Funs0,
+                 erlang:function_exported(?MODULE, FArgs, 1)
+          ],
+  proper_types:oneof([ {call, ?MODULE, F, ?MODULE:FArgs(State)}
+                       || {F, FArgs} <- Funs1
+                     ]).
+
+precondition(S, {call, M, F, Args}) ->
+  Pre = list_to_atom(atom_to_list(F) ++ "_pre"),
+  case erlang:function_exported(M, Pre, 1) of
+    true  -> M:Pre(S);
+    false -> true
+  end
+  andalso
+  case erlang:function_exported(M, Pre, 2) of
+    true  -> M:Pre(S, Args);
+    false -> true
+  end.
+
+next_state(S, Res, {call, M, F, Args}) ->
+  Next = list_to_atom(atom_to_list(F) ++ "_next"),
+  case erlang:function_exported(M, Next, 3) of
+    true  -> M:Next(S, Res, Args);
+    false -> S
+  end.
+
+postcondition(S, {call, M, F, Args}, Res) ->
+  Post = list_to_atom(atom_to_list(F) ++ "_post"),
+  case erlang:function_exported(M, Post, 3) of
+    true  -> M:Post(S, Args, Res);
+    false -> true
+  end.
+
+{{#operations}}
+{{#operation}}
+%%==============================================================================
+%% {{operationId}}
+%%==============================================================================
+
+{{operationId}}({{#allParams}}{{#required}}{{^-first}}, {{/-first}}{{paramName}}{{/required}}{{/allParams}}) ->
+  {{classname}}_api:{{operationId}}({{#allParams}}{{#required}}{{^-first}}, {{/-first}}{{paramName}}{{/required}}{{/allParams}}).
+
+{{operationId}}_args(S) ->
+  Args = [{{#allParams}}{{#required}}{{^-first}}, {{/-first}}{{dataType}}{{/required}}{{/allParams}}],
+  case erlang:function_exported(?MODULE, '{{operationId}}_args_custom', 2) of
+    true -> ?MODULE:{{operationId}}_args_custom(S, Args);
+    false -> Args
+  end.
+
+{{/operation}}
+{{/operations}}
+
+%%==============================================================================
+%% The statem's property
+%%==============================================================================
+
+prop_main() ->
+  setup(),
+  ?FORALL( Cmds
+         , proper_statem:commands(?MODULE)
+         , begin
+             cleanup(),
+             { History
+             , State
+             , Result
+             } = proper_statem:run_commands(?MODULE, Cmds),
+             ?WHENFAIL(
+                io:format("History: ~p\nState: ~p\nResult: ~p\nCmds: ~p\n",
+                          [ History
+                          , State
+                          , Result
+                          , proper_statem:command_names(Cmds)
+                          ]),
+                proper:aggregate( proper_statem:command_names(Cmds)
+                                , Result =:= ok
+                                )
+               )
+           end
+         ).
+
+%%==============================================================================
+%% Include file with setup, cleanup, initial_state
+%% and state transitions callbacks
+%%==============================================================================
+-include("{{classname}}_statem.hrl").
diff --git a/modules/openapi-generator/src/main/resources/erlang-proper/test.mustache b/modules/openapi-generator/src/main/resources/erlang-proper/test.mustache
new file mode 100644
index 0000000000..ac2d2330b3
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/erlang-proper/test.mustache
@@ -0,0 +1,7 @@
+-module(prop_{{packageName}}).
+
+-export([prop_test/0]).
+
+prop_test() ->
+  {ok, _} = application:ensure_all_started({{packageName}}),
+  {{packageName}}_statem:prop_main().
diff --git a/modules/openapi-generator/src/main/resources/erlang-proper/utils.mustache b/modules/openapi-generator/src/main/resources/erlang-proper/utils.mustache
new file mode 100644
index 0000000000..f8adf39c54
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/erlang-proper/utils.mustache
@@ -0,0 +1,66 @@
+-module({{packageName}}_utils).
+
+-export([ request/2
+        , request/4
+        ]).
+
+-type response() :: #{ status  := integer()
+                     , headers := map()
+                     , body    := iolist()
+                     }.
+
+-export_type([response/0]).
+
+-spec request(atom(), string()) -> response().
+request(Method, Url) ->
+  request(Method, Url, undefined, undefined).
+
+-spec request(atom(), iolist(), iolist(), string()) -> response().
+request(Method, Url0, Body, ContentType) ->
+  Url         = binary_to_list(iolist_to_binary(Url0)),
+  Headers     = headers(),
+  Request     = case Body of
+                  undefined -> {Url, Headers};
+                  _         -> {Url, Headers, ContentType, Body}
+                end,
+  HTTPOptions = [{autoredirect, true}],
+  Options     = [],
+  %% Disable pipelining to avoid the socket getting closed during long runs
+  ok = httpc:set_options([ {max_keep_alive_length, 0}
+                         , {max_pipeline_length, 0}
+                         , {max_sessions, 0}
+                         ]),
+  Result = httpc:request(Method, Request, HTTPOptions, Options),
+  {ok, {{=<% %>=}}{{_Ver, Status, _Phrase}, RespHeaders, RespBody}}<%={{ }}=%> = Result,
+
+  Response = #{ status  => Status
+              , headers => maps:from_list(RespHeaders)
+              , body    => RespBody
+              },
+  decode_body(Response).
+
+-spec headers() -> [{string(), string()}].
+headers() ->
+  [ {"Accept",        "application/json"}
+  | basic_auth()
+  ].
+
+-spec basic_auth() -> [{string(), string()}].
+basic_auth() ->
+  case application:get_env({{packageName}}, basic_auth, undefined) of
+    undefined -> [];
+    {Username, Password} ->
+      Credentials = base64:encode_to_string(Username ++ ":" ++ Password),
+      [{"Authorization", "Basic " ++ Credentials}]
+  end.
+
+-spec decode_body(response()) -> response().
+decode_body(#{ headers := #{"content-type" := "application/json"}
+             , body    := Body
+             } = Response) ->
+  Json = jsx:decode( unicode:characters_to_binary(Body)
+                   , [return_maps, {labels, atom}]
+                   ),
+  Response#{body_json => Json};
+decode_body(Response) ->
+  Response.
diff --git a/samples/client/petstore/erlang-proper/.openapi-generator-ignore b/samples/client/petstore/erlang-proper/.openapi-generator-ignore
new file mode 100644
index 0000000000..7484ee590a
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/.openapi-generator-ignore
@@ -0,0 +1,23 @@
+# OpenAPI Generator Ignore
+# Generated by openapi-generator https://github.com/openapitools/openapi-generator
+
+# Use this file to prevent files from being overwritten by the generator.
+# The patterns follow closely to .gitignore or .dockerignore.
+
+# As an example, the C# client generator defines ApiClient.cs.
+# You can make changes and tell OpenAPI Generator to ignore just this file by uncommenting the following line:
+#ApiClient.cs
+
+# You can match any string of characters against a directory, file or extension with a single asterisk (*):
+#foo/*/qux
+# The above matches foo/bar/qux and foo/baz/qux, but not foo/bar/baz/qux
+
+# You can recursively match patterns against a directory, file or extension with a double asterisk (**):
+#foo/**/qux
+# This matches foo/bar/qux, foo/baz/qux, and foo/bar/baz/qux
+
+# You can also negate patterns with an exclamation (!).
+# For example, you can ignore all files in a docs folder with the file extension .md:
+#docs/*.md
+# Then explicitly reverse the ignore rule for a single file:
+#!docs/README.md
diff --git a/samples/client/petstore/erlang-proper/.openapi-generator/VERSION b/samples/client/petstore/erlang-proper/.openapi-generator/VERSION
new file mode 100644
index 0000000000..6d94c9c2e1
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/.openapi-generator/VERSION
@@ -0,0 +1 @@
+3.3.0-SNAPSHOT
\ No newline at end of file
diff --git a/samples/client/petstore/erlang-proper/README.md b/samples/client/petstore/erlang-proper/README.md
new file mode 100644
index 0000000000..cc63f05bdc
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/README.md
@@ -0,0 +1,6 @@
+# OpenAPI client library for Erlang with Erlang QuickCheck generators
+
+## Overview
+
+An Erlang client stub and Erlang QuickCheck generators, generated by
+[OpenAPI Generator](https://openapi-generator.tech) given an OpenAPI spec.
diff --git a/samples/client/petstore/erlang-proper/rebar.config b/samples/client/petstore/erlang-proper/rebar.config
new file mode 100644
index 0000000000..0060c9afec
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/rebar.config
@@ -0,0 +1,7 @@
+{erl_opts, [debug_info, warnings_as_errors]}.
+
+{deps, [{jsx, "2.9.0"}, {proper, "1.3.0"}]}.
+
+{shell, [{apps, [petstore]}]}.
+
+{plugins, [rebar3_proper]}.
diff --git a/samples/client/petstore/erlang-proper/src/model/petstore_api_response.erl b/samples/client/petstore/erlang-proper/src/model/petstore_api_response.erl
new file mode 100644
index 0000000000..495861559a
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/src/model/petstore_api_response.erl
@@ -0,0 +1,19 @@
+-module(petstore_api_response).
+
+-include("petstore.hrl").
+
+-export([petstore_api_response/0]).
+
+-export_type([petstore_api_response/0]).
+
+-type petstore_api_response() ::
+  [ {'code', integer() }
+  | {'type', binary() }
+  | {'message', binary() }
+  ].
+
+petstore_api_response() ->
+  [ {'code', integer() }
+  , {'type', binary() }
+  , {'message', binary() }
+  ].
diff --git a/samples/client/petstore/erlang-proper/src/model/petstore_category.erl b/samples/client/petstore/erlang-proper/src/model/petstore_category.erl
new file mode 100644
index 0000000000..d048667c35
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/src/model/petstore_category.erl
@@ -0,0 +1,17 @@
+-module(petstore_category).
+
+-include("petstore.hrl").
+
+-export([petstore_category/0]).
+
+-export_type([petstore_category/0]).
+
+-type petstore_category() ::
+  [ {'id', integer() }
+  | {'name', binary() }
+  ].
+
+petstore_category() ->
+  [ {'id', integer() }
+  , {'name', binary() }
+  ].
diff --git a/samples/client/petstore/erlang-proper/src/model/petstore_order.erl b/samples/client/petstore/erlang-proper/src/model/petstore_order.erl
new file mode 100644
index 0000000000..360e5cf428
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/src/model/petstore_order.erl
@@ -0,0 +1,25 @@
+-module(petstore_order).
+
+-include("petstore.hrl").
+
+-export([petstore_order/0]).
+
+-export_type([petstore_order/0]).
+
+-type petstore_order() ::
+  [ {'id', integer() }
+  | {'petId', integer() }
+  | {'quantity', integer() }
+  | {'shipDate', datetime() }
+  | {'status', binary() }
+  | {'complete', boolean() }
+  ].
+
+petstore_order() ->
+  [ {'id', integer() }
+  , {'petId', integer() }
+  , {'quantity', integer() }
+  , {'shipDate', datetime() }
+  , {'status', elements([<<"placed">>, <<"approved">>, <<"delivered">>]) }
+  , {'complete', boolean() }
+  ].
diff --git a/samples/client/petstore/erlang-proper/src/model/petstore_pet.erl b/samples/client/petstore/erlang-proper/src/model/petstore_pet.erl
new file mode 100644
index 0000000000..77bbd704fe
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/src/model/petstore_pet.erl
@@ -0,0 +1,25 @@
+-module(petstore_pet).
+
+-include("petstore.hrl").
+
+-export([petstore_pet/0]).
+
+-export_type([petstore_pet/0]).
+
+-type petstore_pet() ::
+  [ {'id', integer() }
+  | {'category', petstore_category:petstore_category() }
+  | {'name', binary() }
+  | {'photoUrls', list(binary()) }
+  | {'tags', list(petstore_tag:petstore_tag()) }
+  | {'status', binary() }
+  ].
+
+petstore_pet() ->
+  [ {'id', integer() }
+  , {'category', petstore_category:petstore_category() }
+  , {'name', binary() }
+  , {'photoUrls', list(binary()) }
+  , {'tags', list(petstore_tag:petstore_tag()) }
+  , {'status', elements([<<"available">>, <<"pending">>, <<"sold">>]) }
+  ].
diff --git a/samples/client/petstore/erlang-proper/src/model/petstore_tag.erl b/samples/client/petstore/erlang-proper/src/model/petstore_tag.erl
new file mode 100644
index 0000000000..31bfe4fadb
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/src/model/petstore_tag.erl
@@ -0,0 +1,17 @@
+-module(petstore_tag).
+
+-include("petstore.hrl").
+
+-export([petstore_tag/0]).
+
+-export_type([petstore_tag/0]).
+
+-type petstore_tag() ::
+  [ {'id', integer() }
+  | {'name', binary() }
+  ].
+
+petstore_tag() ->
+  [ {'id', integer() }
+  , {'name', binary() }
+  ].
diff --git a/samples/client/petstore/erlang-proper/src/model/petstore_user.erl b/samples/client/petstore/erlang-proper/src/model/petstore_user.erl
new file mode 100644
index 0000000000..df35576aa4
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/src/model/petstore_user.erl
@@ -0,0 +1,29 @@
+-module(petstore_user).
+
+-include("petstore.hrl").
+
+-export([petstore_user/0]).
+
+-export_type([petstore_user/0]).
+
+-type petstore_user() ::
+  [ {'id', integer() }
+  | {'username', binary() }
+  | {'firstName', binary() }
+  | {'lastName', binary() }
+  | {'email', binary() }
+  | {'password', binary() }
+  | {'phone', binary() }
+  | {'userStatus', integer() }
+  ].
+
+petstore_user() ->
+  [ {'id', integer() }
+  , {'username', binary() }
+  , {'firstName', binary() }
+  , {'lastName', binary() }
+  , {'email', binary() }
+  , {'password', binary() }
+  , {'phone', binary() }
+  , {'userStatus', integer() }
+  ].
diff --git a/samples/client/petstore/erlang-proper/src/petstore.app.src b/samples/client/petstore/erlang-proper/src/petstore.app.src
new file mode 100644
index 0000000000..dc56ef9bd8
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/src/petstore.app.src
@@ -0,0 +1,21 @@
+{ application, petstore
+, [ {description, "This is a sample server Petstore server. For this sample, you can use the api key &#x60;special-key&#x60; to test the authorization filters."}
+  , {vsn, "0.1.0"}
+  , {registered, []}
+  , { applications
+    , [ kernel
+      , stdlib
+      , ssl
+      , jsx
+      ]
+    }
+  , { env
+    , [ {host, "http://petstore.swagger.io"}
+      , {basic_auth, {"admin", "admin"}}
+      ]
+    }
+  , {modules, []}
+  , {maintainers, []}
+  , {licenses, ["Apache-2.0"]}
+  , {links, []}
+]}.
diff --git a/samples/client/petstore/erlang-proper/src/petstore.hrl b/samples/client/petstore/erlang-proper/src/petstore.hrl
new file mode 100644
index 0000000000..d57c511a5a
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/src/petstore.hrl
@@ -0,0 +1,24 @@
+-compile({no_auto_import,[date/0]}).
+
+-import( petstore_gen
+       , [ binary/0
+         , binary/1
+         , binary/2
+         , integer/0
+         , integer/1
+         , integer/2
+         , boolean/0
+         , list/0
+         , list/1
+         , list/2
+         , list/3
+         , map/0
+         , date/0
+         , datetime/0
+         , any/0
+         , elements/1
+         ]
+       ).
+
+-type date()     :: calendar:date().
+-type datetime() :: calendar:datetime().
diff --git a/samples/client/petstore/erlang-proper/src/petstore_api.erl b/samples/client/petstore/erlang-proper/src/petstore_api.erl
new file mode 100644
index 0000000000..fe3fe661b3
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/src/petstore_api.erl
@@ -0,0 +1,119 @@
+-module(petstore_api).
+
+-export([ create_user/1
+        , create_users_with_array_input/1
+        , create_users_with_list_input/1
+        , delete_user/1
+        , get_user_by_name/1
+        , login_user/2
+        , logout_user/0
+        , update_user/2
+        ]).
+
+-define(BASE_URL, "/v2").
+
+%% @doc Create user
+%% This can only be done by the logged in user.
+-spec create_user(petstore_user:petstore_user()) ->
+  petstore_utils:response().
+create_user(PetstoreUser) ->
+  Method      = post,
+  Host        = application:get_env(petstore, host, "http://localhost:8080"),
+  Path        = ["/user"],
+  Body        = PetstoreUser,
+  ContentType = <<"text/plain">>,
+
+  petstore_utils:request(Method, [Host, ?BASE_URL, Path], jsx:encode(Body), ContentType).
+
+%% @doc Creates list of users with given input array
+%% 
+-spec create_users_with_array_input(list(petstore_user:petstore_user())) ->
+  petstore_utils:response().
+create_users_with_array_input(PetstoreUserArray) ->
+  Method      = post,
+  Host        = application:get_env(petstore, host, "http://localhost:8080"),
+  Path        = ["/user/createWithArray"],
+  Body        = PetstoreUserArray,
+  ContentType = <<"text/plain">>,
+
+  petstore_utils:request(Method, [Host, ?BASE_URL, Path], jsx:encode(Body), ContentType).
+
+%% @doc Creates list of users with given input array
+%% 
+-spec create_users_with_list_input(list(petstore_user:petstore_user())) ->
+  petstore_utils:response().
+create_users_with_list_input(PetstoreUserArray) ->
+  Method      = post,
+  Host        = application:get_env(petstore, host, "http://localhost:8080"),
+  Path        = ["/user/createWithList"],
+  Body        = PetstoreUserArray,
+  ContentType = <<"text/plain">>,
+
+  petstore_utils:request(Method, [Host, ?BASE_URL, Path], jsx:encode(Body), ContentType).
+
+%% @doc Delete user
+%% This can only be done by the logged in user.
+-spec delete_user(binary()) ->
+  petstore_utils:response().
+delete_user(Username) ->
+  Method      = delete,
+  Host        = application:get_env(petstore, host, "http://localhost:8080"),
+  Path        = ["/user/", Username, ""],
+  Body        = [],
+  ContentType = <<"text/plain">>,
+
+  petstore_utils:request(Method, [Host, ?BASE_URL, Path], jsx:encode(Body), ContentType).
+
+%% @doc Get user by user name
+%% 
+-spec get_user_by_name(binary()) ->
+  petstore_utils:response().
+get_user_by_name(Username) ->
+  Method      = get,
+  Host        = application:get_env(petstore, host, "http://localhost:8080"),
+  Path        = ["/user/", Username, ""],
+  Body        = [],
+  ContentType = <<"text/plain">>,
+
+  petstore_utils:request(Method, [Host, ?BASE_URL, Path], jsx:encode(Body), ContentType).
+
+%% @doc Logs user into the system
+%% 
+-spec login_user(binary(), binary()) ->
+  petstore_utils:response().
+login_user(Username, Password) ->
+  Method      = get,
+  Host        = application:get_env(petstore, host, "http://localhost:8080"),
+  Path        = ["/user/login"],
+  Body        = [],
+  ContentType = <<"text/plain">>,
+  QueryString = [<<"username=">>, Username, <<"&">>, <<"password=">>, Password, <<"&">>],
+
+  petstore_utils:request(Method, [Host, ?BASE_URL, Path, <<"?">>, QueryString], jsx:encode(Body), ContentType).
+
+%% @doc Logs out current logged in user session
+%% 
+-spec logout_user() ->
+  petstore_utils:response().
+logout_user() ->
+  Method      = get,
+  Host        = application:get_env(petstore, host, "http://localhost:8080"),
+  Path        = ["/user/logout"],
+  Body        = [],
+  ContentType = <<"text/plain">>,
+
+  petstore_utils:request(Method, [Host, ?BASE_URL, Path], jsx:encode(Body), ContentType).
+
+%% @doc Updated user
+%% This can only be done by the logged in user.
+-spec update_user(binary(), petstore_user:petstore_user()) ->
+  petstore_utils:response().
+update_user(Username, PetstoreUser) ->
+  Method      = put,
+  Host        = application:get_env(petstore, host, "http://localhost:8080"),
+  Path        = ["/user/", Username, ""],
+  Body        = PetstoreUser,
+  ContentType = <<"text/plain">>,
+
+  petstore_utils:request(Method, [Host, ?BASE_URL, Path], jsx:encode(Body), ContentType).
+
diff --git a/samples/client/petstore/erlang-proper/src/petstore_gen.erl b/samples/client/petstore/erlang-proper/src/petstore_gen.erl
new file mode 100644
index 0000000000..fae40e3567
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/src/petstore_gen.erl
@@ -0,0 +1,157 @@
+-module(petstore_gen).
+
+-compile({no_auto_import,[date/0]}).
+
+-include_lib("proper/include/proper_common.hrl").
+
+%%==============================================================================
+%% Exports
+%%==============================================================================
+
+-export([ binary/0
+        , binary/1
+        , binary/2
+        , integer/0
+        , integer/1
+        , integer/2
+        , boolean/0
+        , list/0
+        , list/1
+        , list/2
+        , list/3
+        , map/0
+        , date/0
+        , datetime/0
+        , any/0
+        , elements/1
+        ]).
+
+-define(CHARS, [$a, $b, $c]).
+
+%%==============================================================================
+%% Generators
+%%==============================================================================
+
+binary() -> binary(10).
+
+binary(Min, Max) ->
+  ?LET( {X, N}
+      , { proper_types:elements(?CHARS)
+        , proper_types:choose(Min, Max)
+        }
+      , iolist_to_binary(lists:duplicate(N, X))
+      ).
+
+binary(N) ->
+  ?LET( X
+      , proper_types:elements(?CHARS)
+      , iolist_to_binary(lists:duplicate(N, X))
+      ).
+
+integer() -> proper_types:int().
+
+integer(0) -> proper_types:nat();
+integer(Min) ->
+  ?LET( N
+      , proper_types:nat()
+      , proper_types:choose(Min, Min + N)
+      ).
+
+integer(Min, Max) -> proper_types:choose(Min, Max).
+
+boolean() -> proper_types:bool().
+
+list() -> list(any()).
+
+list(Type) -> proper_types:list(Type).
+
+list(Type, Min) ->
+  ?LET( N
+      , integer(0)
+      , ?LET(X, list(Type, Min, Min + N), X)
+      ).
+
+list(Type, Min, Max) when Min =< Max ->
+  ?LET( {X, Y}
+      , { proper_types:vector(Min, Type)
+        , proper_types:resize(Max - Min, proper_types:list(Type))
+        }
+      , X ++ Y
+      ).
+
+map() -> proper_types:map(any(), any()).
+
+date() ->
+  ?LET( X
+      , ?SUCHTHAT( X
+                 , { year()
+                   , proper_types:choose(1, 12)
+                   , proper_types:choose(1, 31)
+                   }
+                 , calendar:valid_date(X)
+                 )
+      , begin
+          {Year, Month, Day} = X,
+          YearBin  = num_binary_format(Year, "4"),
+          MonthBin = num_binary_format(Month, "2"),
+          DayBin   = num_binary_format(Day, "2"),
+          <<YearBin/binary, "-", MonthBin/binary, "-", DayBin/binary>>
+        end
+      ).
+
+datetime() ->
+  Date = date(),
+  Hour = hour(),
+  ?LET( X
+      , {Date, Hour}
+      , begin
+          {D, H} = X,
+          <<D/binary, "T", H/binary, "+0000">>
+        end
+      ).
+
+any() ->
+  Any = [ binary()
+        , integer()
+        , boolean()
+        %% We don't include lists and maps to avoid huge values
+        %% , list()
+        %% , map()
+        , date()
+        , datetime()
+        ],
+  proper_types:oneof(Any).
+
+elements(Items) ->
+  proper_types:elements(Items).
+
+%%==============================================================================
+%% Internal
+%%==============================================================================
+
+year() ->
+  ?LET( X
+      , proper_types:nat()
+      , 1970 + X
+      ).
+
+hour() ->
+  ?LET( X
+      , { proper_types:choose(0, 23)
+        , proper_types:choose(0, 59)
+        , proper_types:choose(0, 59)
+        , proper_types:choose(0, 999)
+        }
+      , begin
+          {Hours, Mins, Secs, Millis} = X,
+          HoursBin  = num_binary_format(Hours, "2"),
+          MinsBin   = num_binary_format(Mins, "2"),
+          SecsBin   = num_binary_format(Secs, "2"),
+          MillisBin = num_binary_format(Millis, "3"),
+          <<HoursBin/binary, ":", MinsBin/binary, ":",
+            SecsBin/binary, ".", MillisBin/binary>>
+        end
+      ).
+
+num_binary_format(X, N) ->
+  list_to_binary(io_lib:format("~" ++ N ++ "..0B", [X])).
diff --git a/samples/client/petstore/erlang-proper/src/petstore_statem.erl b/samples/client/petstore/erlang-proper/src/petstore_statem.erl
new file mode 100644
index 0000000000..d7e769cdae
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/src/petstore_statem.erl
@@ -0,0 +1,199 @@
+-module(petstore_statem).
+
+-behaviour(proper_statem).
+
+-include("petstore.hrl").
+-include_lib("proper/include/proper_common.hrl").
+-include_lib("stdlib/include/assert.hrl").
+
+-compile(export_all).
+-compile(nowarn_export_all).
+
+%%==============================================================================
+%% PropEr callbacks
+%%==============================================================================
+
+command(State) ->
+  Funs0 = [ {F, list_to_atom(atom_to_list(F) ++ "_args")}
+            || {F, _} <- ?MODULE:module_info(exports)
+          ],
+
+  Funs1 = [ X || {_, FArgs} = X <- Funs0,
+                 erlang:function_exported(?MODULE, FArgs, 1)
+          ],
+  proper_types:oneof([ {call, ?MODULE, F, ?MODULE:FArgs(State)}
+                       || {F, FArgs} <- Funs1
+                     ]).
+
+precondition(S, {call, M, F, Args}) ->
+  Pre = list_to_atom(atom_to_list(F) ++ "_pre"),
+  case erlang:function_exported(M, Pre, 1) of
+    true  -> M:Pre(S);
+    false -> true
+  end
+  andalso
+  case erlang:function_exported(M, Pre, 2) of
+    true  -> M:Pre(S, Args);
+    false -> true
+  end.
+
+next_state(S, Res, {call, M, F, Args}) ->
+  Next = list_to_atom(atom_to_list(F) ++ "_next"),
+  case erlang:function_exported(M, Next, 3) of
+    true  -> M:Next(S, Res, Args);
+    false -> S
+  end.
+
+postcondition(S, {call, M, F, Args}, Res) ->
+  Post = list_to_atom(atom_to_list(F) ++ "_post"),
+  case erlang:function_exported(M, Post, 3) of
+    true  -> M:Post(S, Args, Res);
+    false -> true
+  end.
+
+%%==============================================================================
+%% create_user
+%%==============================================================================
+
+create_user(PetstoreUser) ->
+  petstore_api:create_user(PetstoreUser).
+
+create_user_args(S) ->
+  Args = [petstore_user:petstore_user()],
+  case erlang:function_exported(?MODULE, 'create_user_args_custom', 2) of
+    true -> ?MODULE:create_user_args_custom(S, Args);
+    false -> Args
+  end.
+
+%%==============================================================================
+%% create_users_with_array_input
+%%==============================================================================
+
+create_users_with_array_input(PetstoreUserArray) ->
+  petstore_api:create_users_with_array_input(PetstoreUserArray).
+
+create_users_with_array_input_args(S) ->
+  Args = [list(petstore_user:petstore_user())],
+  case erlang:function_exported(?MODULE, 'create_users_with_array_input_args_custom', 2) of
+    true -> ?MODULE:create_users_with_array_input_args_custom(S, Args);
+    false -> Args
+  end.
+
+%%==============================================================================
+%% create_users_with_list_input
+%%==============================================================================
+
+create_users_with_list_input(PetstoreUserArray) ->
+  petstore_api:create_users_with_list_input(PetstoreUserArray).
+
+create_users_with_list_input_args(S) ->
+  Args = [list(petstore_user:petstore_user())],
+  case erlang:function_exported(?MODULE, 'create_users_with_list_input_args_custom', 2) of
+    true -> ?MODULE:create_users_with_list_input_args_custom(S, Args);
+    false -> Args
+  end.
+
+%%==============================================================================
+%% delete_user
+%%==============================================================================
+
+delete_user(Username) ->
+  petstore_api:delete_user(Username).
+
+delete_user_args(S) ->
+  Args = [binary()],
+  case erlang:function_exported(?MODULE, 'delete_user_args_custom', 2) of
+    true -> ?MODULE:delete_user_args_custom(S, Args);
+    false -> Args
+  end.
+
+%%==============================================================================
+%% get_user_by_name
+%%==============================================================================
+
+get_user_by_name(Username) ->
+  petstore_api:get_user_by_name(Username).
+
+get_user_by_name_args(S) ->
+  Args = [binary()],
+  case erlang:function_exported(?MODULE, 'get_user_by_name_args_custom', 2) of
+    true -> ?MODULE:get_user_by_name_args_custom(S, Args);
+    false -> Args
+  end.
+
+%%==============================================================================
+%% login_user
+%%==============================================================================
+
+login_user(Username, Password) ->
+  petstore_api:login_user(Username, Password).
+
+login_user_args(S) ->
+  Args = [binary(), binary()],
+  case erlang:function_exported(?MODULE, 'login_user_args_custom', 2) of
+    true -> ?MODULE:login_user_args_custom(S, Args);
+    false -> Args
+  end.
+
+%%==============================================================================
+%% logout_user
+%%==============================================================================
+
+logout_user() ->
+  petstore_api:logout_user().
+
+logout_user_args(S) ->
+  Args = [],
+  case erlang:function_exported(?MODULE, 'logout_user_args_custom', 2) of
+    true -> ?MODULE:logout_user_args_custom(S, Args);
+    false -> Args
+  end.
+
+%%==============================================================================
+%% update_user
+%%==============================================================================
+
+update_user(Username, PetstoreUser) ->
+  petstore_api:update_user(Username, PetstoreUser).
+
+update_user_args(S) ->
+  Args = [binary(), petstore_user:petstore_user()],
+  case erlang:function_exported(?MODULE, 'update_user_args_custom', 2) of
+    true -> ?MODULE:update_user_args_custom(S, Args);
+    false -> Args
+  end.
+
+
+%%==============================================================================
+%% The statem's property
+%%==============================================================================
+
+prop_main() ->
+  setup(),
+  ?FORALL( Cmds
+         , proper_statem:commands(?MODULE)
+         , begin
+             cleanup(),
+             { History
+             , State
+             , Result
+             } = proper_statem:run_commands(?MODULE, Cmds),
+             ?WHENFAIL(
+                io:format("History: ~p\nState: ~p\nResult: ~p\nCmds: ~p\n",
+                          [ History
+                          , State
+                          , Result
+                          , proper_statem:command_names(Cmds)
+                          ]),
+                proper:aggregate( proper_statem:command_names(Cmds)
+                                , Result =:= ok
+                                )
+               )
+           end
+         ).
+
+%%==============================================================================
+%% Include file with setup, cleanup, initial_state
+%% and state transitions callbacks
+%%==============================================================================
+-include("petstore_statem.hrl").
diff --git a/samples/client/petstore/erlang-proper/src/petstore_statem.hrl b/samples/client/petstore/erlang-proper/src/petstore_statem.hrl
new file mode 100644
index 0000000000..7b4dd931aa
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/src/petstore_statem.hrl
@@ -0,0 +1,25 @@
+%%==============================================================================
+%% Setup
+%%==============================================================================
+
+setup() -> ok.
+
+%%==============================================================================
+%% Cleanup
+%%==============================================================================
+
+cleanup() -> ok.
+
+%%==============================================================================
+%% Initial State
+%%==============================================================================
+
+initial_state() -> #{}.
+
+%%==============================================================================
+%% State transitions callbacks
+%%
+%% operation_pre(State) -> true.
+%% operation_next(State, Result, Args) -> State.
+%% operation_post(State, Args, Result) -> true.
+%%==============================================================================
diff --git a/samples/client/petstore/erlang-proper/src/petstore_utils.erl b/samples/client/petstore/erlang-proper/src/petstore_utils.erl
new file mode 100644
index 0000000000..054228c13d
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/src/petstore_utils.erl
@@ -0,0 +1,66 @@
+-module(petstore_utils).
+
+-export([ request/2
+        , request/4
+        ]).
+
+-type response() :: #{ status  := integer()
+                     , headers := map()
+                     , body    := iolist()
+                     }.
+
+-export_type([response/0]).
+
+-spec request(atom(), string()) -> response().
+request(Method, Url) ->
+  request(Method, Url, undefined, undefined).
+
+-spec request(atom(), iolist(), iolist(), string()) -> response().
+request(Method, Url0, Body, ContentType) ->
+  Url         = binary_to_list(iolist_to_binary(Url0)),
+  Headers     = headers(),
+  Request     = case Body of
+                  undefined -> {Url, Headers};
+                  _         -> {Url, Headers, ContentType, Body}
+                end,
+  HTTPOptions = [{autoredirect, true}],
+  Options     = [],
+  %% Disable pipelining to avoid the socket getting closed during long runs
+  ok = httpc:set_options([ {max_keep_alive_length, 0}
+                         , {max_pipeline_length, 0}
+                         , {max_sessions, 0}
+                         ]),
+  Result = httpc:request(Method, Request, HTTPOptions, Options),
+  {ok, {{_Ver, Status, _Phrase}, RespHeaders, RespBody}} = Result,
+
+  Response = #{ status  => Status
+              , headers => maps:from_list(RespHeaders)
+              , body    => RespBody
+              },
+  decode_body(Response).
+
+-spec headers() -> [{string(), string()}].
+headers() ->
+  [ {"Accept",        "application/json"}
+  | basic_auth()
+  ].
+
+-spec basic_auth() -> [{string(), string()}].
+basic_auth() ->
+  case application:get_env(petstore, basic_auth, undefined) of
+    undefined -> [];
+    {Username, Password} ->
+      Credentials = base64:encode_to_string(Username ++ ":" ++ Password),
+      [{"Authorization", "Basic " ++ Credentials}]
+  end.
+
+-spec decode_body(response()) -> response().
+decode_body(#{ headers := #{"content-type" := "application/json"}
+             , body    := Body
+             } = Response) ->
+  Json = jsx:decode( unicode:characters_to_binary(Body)
+                   , [return_maps, {labels, atom}]
+                   ),
+  Response#{body_json => Json};
+decode_body(Response) ->
+  Response.
diff --git a/samples/client/petstore/erlang-proper/test/prop_petstore.erl b/samples/client/petstore/erlang-proper/test/prop_petstore.erl
new file mode 100644
index 0000000000..558e99f1c3
--- /dev/null
+++ b/samples/client/petstore/erlang-proper/test/prop_petstore.erl
@@ -0,0 +1,7 @@
+-module(prop_petstore).
+
+-export([prop_test/0]).
+
+prop_test() ->
+  {ok, _} = application:ensure_all_started(petstore),
+  petstore_statem:prop_main().