diff --git a/README.md b/README.md
index 4b4548a2e49a..9f4bc162012c 100644
--- a/README.md
+++ b/README.md
@@ -447,6 +447,7 @@ SYNOPSIS
                 [--remove-operation-id-prefix]
                 [--reserved-words-mappings <reserved word mappings>...]
                 [(-s | --skip-overwrite)] [--skip-validate-spec]
+                [--strict-spec <true/false strict behavior>]
                 [(-t <template directory> | --template-dir <template directory>)]
                 [--type-mappings <type mappings>...] [(-v | --verbose)]
 
diff --git a/docs/usage.md b/docs/usage.md
index 880f541841d8..8e09370b61e4 100644
--- a/docs/usage.md
+++ b/docs/usage.md
@@ -239,7 +239,9 @@ SYNOPSIS
                 [--api-package <api package>] [--artifact-id <artifact id>]
                 [--artifact-version <artifact version>]
                 [(-c <configuration file> | --config <configuration file>)]
-                [-D <system properties>...] [--enable-post-process-file]
+                [-D <system properties>...]
+                [(-e <templating engine> | --engine <templating engine>)]
+                [--enable-post-process-file]
                 [(-g <generator name> | --generator-name <generator name>)]
                 [--generate-alias-as-model] [--git-repo-id <git repo id>]
                 [--git-user-id <git user id>] [--group-id <group id>]
@@ -259,6 +261,7 @@ SYNOPSIS
                 [--remove-operation-id-prefix]
                 [--reserved-words-mappings <reserved word mappings>...]
                 [(-s | --skip-overwrite)] [--skip-validate-spec]
+                [--strict-spec <true/false strict behavior>]
                 [(-t <template directory> | --template-dir <template directory>)]
                 [--type-mappings <type mappings>...] [(-v | --verbose)]
 
@@ -289,9 +292,11 @@ OPTIONS
             artifact version in generated pom.xml
 
         -c <configuration file>, --config <configuration file>
-            Path to json configuration file. File content should be in a json
-            format {"optionKey":"optionValue", "optionKey1":"optionValue1"...}
-            Supported options can be different for each language. Run
+            Path to configuration file configuration file. It can be json or
+            yaml.If file is json, the content should have the format
+            {"optionKey":"optionValue", "optionKey1":"optionValue1"...}.If file
+            is yaml, the content should have the format optionKey:
+            optionValueSupported options can be different for each language. Run
             config-help -g {generator name} command for language specific config
             options.
 
@@ -299,11 +304,17 @@ OPTIONS
             sets specified system properties in the format of
             name=value,name=value (or multiple options, each with name=value)
 
+        -e <templating engine>, --engine <templating engine>
+            templating engine: "mustache" (default) or "handlebars" (beta)
+
         --enable-post-process-file
             enablePostProcessFile
 
         -g <generator name>, --generator-name <generator name>
-            generator to use (see langs command for list)
+            generator to use (see list command for list)
+
+        --generate-alias-as-model
+            Generate alias to map, array as models
 
         --git-repo-id <git repo id>
             Git repo ID, e.g. openapi-generator.
@@ -354,6 +365,9 @@ OPTIONS
             piping the JSON output of debug options (e.g. `-DdebugOperations`)
             to an external parser directly while testing a generator.
 
+        --minimal-update
+            Only write output files that have changed.
+
         --model-name-prefix <model name prefix>
             Prefix that will be prepended to all model names. Default is the
             empty string.
@@ -368,6 +382,9 @@ OPTIONS
         -o <output directory>, --output <output directory>
             where to write the generated files (current dir by default)
 
+        --package-name <package name>
+            package for generated classes (where supported)
+
         --release-note <release note>
             Release note, default to 'Minor update'.
 
@@ -386,12 +403,17 @@ OPTIONS
         --skip-validate-spec
             Skips the default behavior of validating an input specification.
 
+        --strict-spec <true/false strict behavior>
+            'MUST' and 'SHALL' wording in OpenAPI spec is strictly adhered to.
+            e.g. when false, no fixes will be applied to documents which pass
+            validation but don't follow the spec.
+
         -t <template directory>, --template-dir <template directory>
             folder containing the template files
 
         --type-mappings <type mappings>
             sets mappings between OpenAPI spec types and generated code types in
-            the format of OpenaAPIType=generatedType,OpenAPIType=generatedType.
+            the format of OpenAPIType=generatedType,OpenAPIType=generatedType.
             For example: array=List,map=Map,string=String. You can also have
             multiple occurrences of this option.
 
diff --git a/modules/openapi-generator-cli/src/main/java/org/openapitools/codegen/cmd/Generate.java b/modules/openapi-generator-cli/src/main/java/org/openapitools/codegen/cmd/Generate.java
index 11c0834ddc4f..62924e2b6ab9 100644
--- a/modules/openapi-generator-cli/src/main/java/org/openapitools/codegen/cmd/Generate.java
+++ b/modules/openapi-generator-cli/src/main/java/org/openapitools/codegen/cmd/Generate.java
@@ -214,6 +214,12 @@ public class Generate implements Runnable {
             description = "Skips the default behavior of validating an input specification.")
     private Boolean skipValidateSpec;
 
+    @Option(name = {"--strict-spec"},
+            title = "true/false strict behavior",
+            description = "'MUST' and 'SHALL' wording in OpenAPI spec is strictly adhered to. e.g. when false, no fixes will be applied to documents which pass validation but don't follow the spec.",
+            arity = 1)
+    private Boolean strictSpecBehavior;
+
     @Option(name = {"--log-to-stderr"},
             title = "Log to STDERR",
             description = "write all log messages (not just errors) to STDOUT."
@@ -368,10 +374,15 @@ public void run() {
         if (generateAliasAsModel != null) {
             configurator.setGenerateAliasAsModel(generateAliasAsModel);
         }
+
         if (minimalUpdate != null) {
             configurator.setEnableMinimalUpdate(minimalUpdate);
         }
 
+        if (strictSpecBehavior != null) {
+            configurator.setStrictSpecBehavior(strictSpecBehavior);
+        }
+
         applySystemPropertiesKvpList(systemProperties, configurator);
         applyInstantiationTypesKvpList(instantiationTypes, configurator);
         applyImportMappingsKvpList(importMappings, configurator);
diff --git a/modules/openapi-generator-cli/src/test/java/org/openapitools/codegen/cmd/GenerateTest.java b/modules/openapi-generator-cli/src/test/java/org/openapitools/codegen/cmd/GenerateTest.java
index 882424341c65..d8812b5c8d1f 100644
--- a/modules/openapi-generator-cli/src/test/java/org/openapitools/codegen/cmd/GenerateTest.java
+++ b/modules/openapi-generator-cli/src/test/java/org/openapitools/codegen/cmd/GenerateTest.java
@@ -277,6 +277,26 @@ public void testSkipOverwrite() throws Exception {
         };
     }
 
+    @Test
+    public void testStrictSpec() throws Exception {
+
+        setupAndRunGenericTest("--strict-spec", "true");
+        new FullVerifications() {
+            {
+                configurator.setStrictSpecBehavior(true);
+                times = 1;
+            }
+        };
+
+        setupAndRunGenericTest("--strict-spec", "false");
+        new FullVerifications() {
+            {
+                configurator.setStrictSpecBehavior(false);
+                times = 1;
+            }
+        };
+    }
+
     @Test
     public void testPackageName() throws Exception {
         final String value = "io.foo.bar.baz";
diff --git a/modules/openapi-generator-maven-plugin/README.md b/modules/openapi-generator-maven-plugin/README.md
index 1489b1f2b287..6d71205c51eb 100644
--- a/modules/openapi-generator-maven-plugin/README.md
+++ b/modules/openapi-generator-maven-plugin/README.md
@@ -57,6 +57,7 @@ mvn clean compile
 - `logToStderr` - write all log messages (not just errors) to STDOUT
 - `enablePostProcessFile` - enable file post-processing hook
 - `skipValidateSpec` - Whether or not to skip validating the input spec prior to generation. By default, invalid specifications will result in an error.
+- `strictSpec` - Whether or not to treat an input document strictly against the spec. 'MUST' and 'SHALL' wording in OpenAPI spec is strictly adhered to. e.g. when false, no fixes will be applied to documents which pass validation but don't follow the spec.
 - `generateAliasAsModel` - generate alias (array, map) as model
 - `generateApis` - generate the apis (`true` by default)
 - `generateApiTests` - generate the api tests (`true` by default. Only available if `generateApis` is `true`)
diff --git a/modules/openapi-generator-maven-plugin/src/main/java/org/openapitools/codegen/plugin/CodeGenMojo.java b/modules/openapi-generator-maven-plugin/src/main/java/org/openapitools/codegen/plugin/CodeGenMojo.java
index 10521857535c..791c83014181 100644
--- a/modules/openapi-generator-maven-plugin/src/main/java/org/openapitools/codegen/plugin/CodeGenMojo.java
+++ b/modules/openapi-generator-maven-plugin/src/main/java/org/openapitools/codegen/plugin/CodeGenMojo.java
@@ -235,6 +235,12 @@ public class CodeGenMojo extends AbstractMojo {
     @Parameter(name = "skipValidateSpec", required = false)
     private Boolean skipValidateSpec;
 
+    /**
+     * To treat a document strictly against the spec.
+     */
+    @Parameter(name = "strictSpec", required = false)
+    private Boolean strictSpecBehavior;
+
     /**
      * To generate alias (array, map) as model
      */
@@ -459,6 +465,10 @@ public void execute() throws MojoExecutionException {
                 configurator.setValidateSpec(!skipValidateSpec);
             }
 
+            if (strictSpecBehavior != null) {
+                configurator.setStrictSpecBehavior(strictSpecBehavior);
+            }
+
             if (logToStderr != null) {
                 configurator.setLogToStderr(logToStderr);
             }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConfig.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConfig.java
index 4ebbdf5c6370..137676771eb1 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConfig.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConfig.java
@@ -270,4 +270,8 @@ public interface CodegenConfig {
     public boolean isEnableMinimalUpdate();
 
     public void setEnableMinimalUpdate(boolean isEnableMinimalUpdate);
+
+    boolean isStrictSpecBehavior();
+
+    void setStrictSpecBehavior(boolean strictSpecBehavior);
 }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
index 5f7693a97108..4c45be94b17d 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
@@ -118,6 +118,9 @@ public class DefaultCodegen implements CodegenConfig {
     // flag to indicate whether to only update files whose contents have changed
     protected boolean enableMinimalUpdate = false;
 
+    // acts strictly upon a spec, potentially modifying it to have consistent behavior across generators.
+    protected boolean strictSpecBehavior = true;
+
     // make openapi available to all methods
     protected OpenAPI openAPI;
 
@@ -2387,11 +2390,13 @@ public CodegenOperation fromOperation(String path,
         }
         operationId = removeNonNameElementToCamelCase(operationId);
 
-        if (path.startsWith("/")) {
-            op.path = path;
-        } else {
+        if (isStrictSpecBehavior() && !path.startsWith("/")) {
+            // modifies an operation.path to strictly conform to OpenAPI Spec
             op.path = "/" + path;
+        } else {
+            op.path = path;
         }
+
         op.operationId = toOperationId(operationId);
         op.summary = escapeText(operation.getSummary());
         op.unescapedNotes = operation.getDescription();
@@ -4900,4 +4905,24 @@ public void setEnableMinimalUpdate(boolean enableMinimalUpdate) {
         this.enableMinimalUpdate = enableMinimalUpdate;
     }
 
+    /**
+     * Indicates whether the codegen configuration should treat documents as strictly defined by the OpenAPI specification.
+     *
+     * @return true to act strictly upon spec documents, potentially modifying the spec to strictly fit the spec.
+     */
+    @Override
+    public boolean isStrictSpecBehavior() {
+        return this.strictSpecBehavior;
+    }
+
+    /**
+     * Sets the boolean valid indicating whether generation will work strictly against the specification, potentially making
+     * minor changes to the input document.
+     *
+     * @param strictSpecBehavior true if we will behave strictly, false to allow specification documents which pass validation to be loosely interpreted against the spec.
+     */
+    @Override
+    public void setStrictSpecBehavior(final boolean strictSpecBehavior) {
+        this.strictSpecBehavior = strictSpecBehavior;
+    }
 }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/CodegenConfigurator.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/CodegenConfigurator.java
index 0e8269987ba9..aea78d7a6961 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/CodegenConfigurator.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/CodegenConfigurator.java
@@ -85,6 +85,7 @@ public class CodegenConfigurator implements Serializable {
     private boolean validateSpec;
     private boolean enablePostProcessFile;
     private boolean enableMinimalUpdate;
+    private boolean strictSpecBehavior;
     private String templateDir;
     private String templatingEngineName;
     private String auth;
@@ -117,6 +118,7 @@ public class CodegenConfigurator implements Serializable {
 
     public CodegenConfigurator() {
         this.validateSpec = true;
+        this.strictSpecBehavior = true;
         this.setOutputDir(".");
     }
 
@@ -252,6 +254,15 @@ public CodegenConfigurator setModelNameSuffix(String suffix) {
         return this;
     }
 
+    public boolean isStrictSpecBehavior() {
+        return strictSpecBehavior;
+    }
+
+    public CodegenConfigurator setStrictSpecBehavior(boolean strictSpecBehavior) {
+        this.strictSpecBehavior = strictSpecBehavior;
+        return this;
+    }
+
     public boolean isVerbose() {
         return verbose;
     }
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultGeneratorTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultGeneratorTest.java
index be1c745fe4ae..89ebd814187c 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultGeneratorTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultGeneratorTest.java
@@ -48,7 +48,35 @@ public void testProcessPaths() throws Exception {
         Assert.assertEquals(defaultList.get(3).path, "/path4");
         Assert.assertEquals(defaultList.get(3).allParams.size(), 1);
     }
-    
+
+
+    @Test
+    public void testNonStrictProcessPaths() throws Exception {
+        OpenAPI openAPI = TestUtils.createOpenAPI();
+        openAPI.setPaths(new Paths());
+        openAPI.getPaths().addPathItem("path1/", new PathItem().get(new Operation().operationId("op1").responses(new ApiResponses().addApiResponse("201", new ApiResponse().description("OK")))));
+        openAPI.getPaths().addPathItem("path2/", new PathItem().get(new Operation().operationId("op2").addParametersItem(new QueryParameter().name("p1").schema(new StringSchema())).responses(new ApiResponses().addApiResponse("201", new ApiResponse().description("OK")))));
+
+        ClientOptInput opts = new ClientOptInput();
+        opts.setOpenAPI(openAPI);
+        CodegenConfig config = new DefaultCodegen();
+        config.setStrictSpecBehavior(false);
+        opts.setConfig(config);
+        opts.setOpts(new ClientOpts());
+
+        DefaultGenerator generator = new DefaultGenerator();
+        generator.opts(opts);
+        Map<String, List<CodegenOperation>> result = generator.processPaths(openAPI.getPaths());
+        Assert.assertEquals(result.size(), 1);
+        List<CodegenOperation> defaultList = result.get("Default");
+        Assert.assertEquals(defaultList.size(), 2);
+        Assert.assertEquals(defaultList.get(0).path, "path1/");
+        Assert.assertEquals(defaultList.get(0).allParams.size(), 0);
+        Assert.assertEquals(defaultList.get(1).path, "path2/");
+        Assert.assertEquals(defaultList.get(1).allParams.size(), 1);
+    }
+
+
     @Test
     public void minimalUpdateTest() throws IOException {
         OpenAPI openAPI = TestUtils.createOpenAPI();