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title: Implementing OAS, RAML, AsyncAPI, and GraphQL APIs
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product: Anypoint Code Builder
version: master
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# Implementing OAS, RAML, AsyncAPI, and GraphQL APIs

> For the full documentation index, see: https://docs.mulesoft.com/llms.txt

After you create your API spec, use Anypoint Code Builder to scaffold your API into a Mule project
for your implementation or integration.

Anypoint Code Builder supports scaffolding these schema fragment files if they’re referenced from
API specs:

<table><colgroup><col> <col> <col> <col></colgroup><thead><tr><th></th><th>Avro</th><th>JSON</th><th>RAML</th></tr></thead><tbody><tr><td><p><strong>AsyncAPI</strong></p></td><td><p>Yes</p></td><td><p>Yes</p></td><td><p>No</p></td></tr><tr><td><p><strong>GraphQL</strong></p></td><td><p>No</p></td><td><p>No</p></td><td><p>Yes</p></td></tr><tr><td><p><strong>OData</strong></p></td><td><p>No</p></td><td><p>No</p></td><td><p>Yes</p></td></tr><tr><td><p><strong>REST</strong></p></td><td><p>No</p></td><td><p>Yes</p></td><td><p>Yes</p></td></tr><tr><td><p><strong>SOAP</strong></p></td><td><p>No</p></td><td><p>No</p></td><td><p>Yes</p></td></tr></tbody></table>

If you add a fragment that isn’t supported, the scaffolder doesn’t add these fragments as project
dependencies when you import the spec from Exchange. However, you can scaffold schemas that are
specified inline within the spec.

For OAS and JSON schema, you can also specify fragment files that you create manually within the
implementation or integration project directory.

Anypoint Code Builder uses the configuration defined in the spec to autogenerate a basic interface
in your implementation project. This interface includes flows for each endpoint or operation, a
built-in XML-based router, and error handlers, which you then implement within a Mule application.

The process you use to implement your API depends on whether you already created a project for your
integration or implementation, or published the spec to Exchange:

- To scaffold an API using a spec from Exchange into:

  - A new project, see [Scaffold an API into a New Project](#scaffold-new-integration).

  - An existing project, see [Import an API Spec into a Project](#import-spec-into-project).

- To update your project with the latest changes to a spec in Exchange, see
  [Re-scaffold an API Specification into a Project](#re-scaffold-spec).

- To scaffold and re-scaffold an API into a project without publishing the spec to Exchange, see
  [Iteratively Design and Implement APIs](https://docs.mulesoft.com/anypoint-code-builder/imp-implement-local-apis).

## Before You Begin

- [Set up and access Anypoint Code Builder](https://docs.mulesoft.com/anypoint-code-builder/start-acb).

- [Create and test your API spec](https://docs.mulesoft.com/anypoint-code-builder/des-create-api-specs).

- [Publish your API spec to Exchange](https://docs.mulesoft.com/anypoint-code-builder/des-publish-api-spec-to-exchange).

- Optionally, [create your integration project (Mule app)](https://docs.mulesoft.com/anypoint-code-builder/int-create-integrations).

- If your API spec is OAS 3.1, make sure your project uses Mule runtime 4.13 or later and APIkit for
  Mule 4 1.13.2 or later.

## Scaffold an API into a New Project

If you have not already created a project, use Anypoint Code Builder to scaffold the API in a new
Mule project:

1.  In the activity bar, click the ![](/mulesoft/current/en-us/anypoint-code-builder/_images/icon-ms-logo.png) (**Anypoint Code Builder**) icon.

    ![Anypoint Code Builder icon highlighted in the activity bar](/mulesoft/current/en-us/anypoint-code-builder/_images/anypoint-code-builder-view.png)

2.  From **Create**, click **Implement an API**:

    ![<strong>Implement an API</strong> link highlighted in the <strong>Getting Started</strong> section](/mulesoft/current/en-us/anypoint-code-builder/_images/implement-api-option-mat.png)

3.  Complete the **Implement an API Specification** form:

    ![Form for starting an implementation project](/mulesoft/current/en-us/anypoint-code-builder/_images/implement-api-configure-in-task.png)

    <table><colgroup><col> <col></colgroup><thead><tr><th>Field Name</th><th>Field Value</th></tr></thead><tbody><tr><td><div><div><p><strong>Project Name</strong></p></div></div></td><td><div><div><p>Unique name for your project.</p></div><div><p>This name is used as the title and name of the project file. For example, if the project name is <em>My Project</em>, the project file name is <code>my-project</code>.</p></div></div></td></tr><tr><td><div><div><p><strong>Project Location</strong></p></div></div></td><td><div><div><p>Your home directory or another directory you create.</p></div><div><p>See <a href="https://docs.mulesoft.com/anypoint-code-builder/start-add-folders">Adding Folders to Your Home Directory</a>.</p></div><div><p>Don’t create the project within another project directory.</p></div></div></td></tr><tr><td><div><div><p><strong>Search an API Specification from Exchange</strong></p></div></div></td><td><div><div><p>Name of the specification in Exchange. Search results can include OAS, RAML, AsyncAPI, and GraphQL specifications. Activate <strong>Show filters</strong> to narrow your search results. See <a href="https://docs.mulesoft.com/anypoint-code-builder/imp-filter-search-results">Filtering Search Results</a> for more information. To implement a gRPC API spec, see <a href="https://docs.mulesoft.com/anypoint-code-builder/imp-implement-grpc-api-spec">Implementing a gRPC API Specification with Anypoint Code Builder</a>.</p></div></div></td></tr><tr><td><div><div><p><strong>Mule runtime</strong></p></div></div></td><td><div><div><p>Mule runtime version to use for your project.</p></div></div></td></tr><tr><td><div><div><p><strong>Java Version</strong></p></div></div></td><td><div><div><p>Java version to use for Mule.</p></div></div></td></tr></tbody></table>

    You can select from locally available Mule runtime and Java versions. The dropdown shows only
    the Mule runtime versions that are installed on your local disk, including bundled Mule runtime
    versions that are available immediately after installation. Anypoint Code Builder saves your
    version settings to the project’s `mule-artifact.json` file. Bundled Mule runtime versions
    enable instant project opening and design. To install additional Mule runtime versions, use the
    `MuleSoft: Install Runtime` command.

    ![Search an API from Exchange](/mulesoft/current/en-us/anypoint-code-builder/_images/imp-api-search.png)

    The form shows the selected API spec, for example:

    ![OAS Example API selected in the Implement an API Specification form](/mulesoft/current/en-us/anypoint-code-builder/_images/imp-api-selected.png)

4.  Click **Create Project**.

    When you create the project, Anypoint Code Builder:

    - Adds the API spec as a dependency in your project’s `pom.xml` file:

      ```XML
      <dependency>
          <groupId>e91cab06-650b-4634-9c6f-5bc4f4fc4d17</groupId>
          <artifactId>OAS-Example</artifactId>
          <version>1.0.1</version>
          <classifier>oas</classifier>
          <type>zip</type>
      </dependency>
      ```

    - Adds the Mule and Java versions to the project’s `mule-artifact.json` file.

    - Scaffolds your API into the new Mule project and opens the configuration XML file.

      The configuration XML file includes the interface for your implementation project, with flows
      for each endpoint in the spec, error handlers, and a built-in router, for example:

      ![OAS Example Integration in Anypoint Code Builder](/mulesoft/current/en-us/anypoint-code-builder/_images/imp-api-scaffolded.png) This
      example includes:

      - The main flow

      - An HTTP Listener with a built-in router

      - Several error handlers

      For GraphQL APIs, Anypoint Code Builder also creates a data fetcher
      (`<graphql-router:data-fetcher>`) as a source for each Mule flow. See the
      [Implement a GraphQL API](https://docs.mulesoft.com/anypoint-code-builder/tut-graphql-implement-api) tutorial for an example GraphQL API and
      [Mapping a GraphQL API to Your Data Sources](https://docs.mulesoft.com/apikit/latest/apikit-graphql-api-mapping) for
      more information about data fetchers.

You can now implement the interface within the Mule app.

## Import an API Spec into a Project

If you have [created an integration project](https://docs.mulesoft.com/anypoint-code-builder/int-create-integrations), you can scaffold an interface
into the project by importing an API spec from Exchange. In this case, Anypoint Code Builder creates
a separate configuration XML file for the interface in your integration project.

1.  In Anypoint Code Builder, open your integration project in the Explorer view, for example,
    `my-project-name`.

2.  Open the Command Palette.

    Show me how

    - Use the keyboard shortcuts:

      - Mac: Cmd+Shift+p

      - Windows: Ctrl+Shift+p

    - Select **View** > **Command Palette**.

3.  Provide the following command:

    ```command
    MuleSoft: Import Asset from Exchange
    ```

4.  Depending on the language of your API spec, select one of these options:

    - **Rest API** for OAS or RAML

    - **GraphQL API**

5.  If prompted, click **Allow** to allow sign in using Anypoint Platform and select the business
    group.

6.  Type the name of the API spec, and press Enter.

7.  Wait for Anypoint Code Builder to load a list of matches to the name.

    ![Assets from Exchange dropdown](/mulesoft/current/en-us/anypoint-code-builder/_images/imp-assets-from-exchange.png)

8.  Select the API spec to import.

9.  At the prompt, select the version of the API spec, such as `v1.0.1`.

10. When prompted to scaffold the API dependency, select **Yes**.

    When you scaffold the API dependency, Anypoint Code Builder:

    - Adds the API spec as a dependency in your project’s `pom.xml` file:

      ```XML
      <dependency>
          <groupId>e91cab06-650b-4634-9c6f-5bc4f4fc4d17</groupId>
          <artifactId>OAS-Example</artifactId>
          <version>1.0.1</version>
          <classifier>oas</classifier>
          <type>zip</type>
      </dependency>
      ```

    - Adds the Mule and Java versions to the `mule-artifact.json` file:

      ```XML
      {
          "minMuleVersion": "4.6.2",
          "javaSpecificationVersions": [
              "11"
          ]
      }
      ```

    - Adds a new configuration XML file, such as `oas-example.xml`, to the project:

      ![New configuration file in the Explorer view](/mulesoft/current/en-us/anypoint-code-builder/_images/imp-new-config-file.png)

      The new configuration XML file includes the interface for your integration project, with flows
      for each endpoint in the spec, error handlers, and a built-in router, for example:

      ![OAS Example Integration in Anypoint Code Builder](/mulesoft/current/en-us/anypoint-code-builder/_images/imp-api-imported.png)

      This example includes:

      - The main flow

      - An HTTP Listener with a built-in router

      - Several error handlers

        For GraphQL APIs, Anypoint Code Builder also creates a data fetcher
        (`<graphql-router:data-fetcher>`) as a source for each Mule flow. See the
        [Implement a GraphQL API](https://docs.mulesoft.com/anypoint-code-builder/tut-graphql-implement-api) tutorial for an example GraphQL API and
        [Mapping a GraphQL API to Your Data Sources](https://docs.mulesoft.com/apikit/latest/apikit-graphql-api-mapping)
        for more information about data fetchers.

You can now implement the interface within the Mule app.

## Re-scaffold an API Specification into a Project

Re-scaffolding enables you to update a project with the latest changes and version of an API spec in
Anypoint Exchange. Re-scaffolding updates the configuration XML and `pom.xml` in your project. To
re-scaffold a spec defined in a local API design project that is not published to Exchange, see
[Iteratively Design and Implement APIs](https://docs.mulesoft.com/anypoint-code-builder/imp-implement-local-apis), instead.

This procedure assumes that an updated version of the spec is available from Exchange, for example,
a 2.0.0 version:

![Selecting a new version of an API spec from Exchange](/mulesoft/current/en-us/anypoint-code-builder/_images/imp-assets-from-exchange-multiversion.png)

1.  In Anypoint Code Builder, open your implementation project in the Explorer view, for example,
    `my-implementation-project`.

2.  Open the Command Palette.

    Show me how

    - Use the keyboard shortcuts:

      - Mac: Cmd+Shift+p

      - Windows: Ctrl+Shift+p

    - Select **View** > **Command Palette**.

3.  Provide the following command:

    ```command
    MuleSoft: Import Asset from Exchange
    ```

4.  Depending on the language of your API spec, select one of these options:

    - **Rest API** for OAS or RAML

    - **GraphQL API**

5.  If prompted, click **Allow** to allow sign in using Anypoint Platform and select the business
    group.

6.  Type the name of the API spec, and press Enter.

7.  Wait for Anypoint Code Builder to load a list of matches to the name.

    ![Assets from Exchange dropdown](/mulesoft/current/en-us/anypoint-code-builder/_images/imp-assets-from-exchange-multiversion.png)

8.  At the prompt, select the version of the API spec, such as `v2.0.0`.

9.  When prompted to scaffold the API dependency, select **Yes**.

    When you scaffold the API dependency, Anypoint Code Builder:

    - Adds the API spec as a dependency in your project’s `pom.xml` file:

      ```XML
      <dependency>
          <groupId>e91cab06-650b-4634-9c6f-5bc4f4fc4d17</groupId>
          <artifactId>phoneSync1005</artifactId>
          <version>2.0.0</version>
          <classifier>oas</classifier>
          <type>zip</type>
      </dependency>
      ```

    - Updates the configuration XML file that contains the interface for your project with the
      changes to the imported spec.

10. Check for the changes to your implementation project.

    For example, if the updated spec adds a new endpoint, the configuration XML for the
    implementation project has a new flow for the endpoint.

11. If the spec introduced a new version number, open the `pom.xml`, and search for the new version
    of the dependency for the `artifactID` of the re-scaffolded spec.

## Tour the Interface File

After you scaffold your API spec into an interface, examine the scaffolded flows and error handlers
for your interface in the UI canvas and code editor.

![Scaffolded flows in the Canvas](/mulesoft/current/en-us/anypoint-code-builder/_images/imp-scaffolded-flow-canvas.png)

1.  In the Explorer view, open the configuration XML file for your interface.

2.  Click the ![](/mulesoft/current/en-us/anypoint-code-builder/_images/icon-tree-view.png) (**Show Mule graphical mode**) icon in the activity
    bar to open the canvas if it doesn’t open automatically.

3.  Click **Flow List** to navigate through flows:

    ![Flow List example](/mulesoft/current/en-us/anypoint-code-builder/_images/int-flow-list.png)

4.  In the code editor, locate the flows created for the endpoints in your API spec.

    Example Flow

    ```xml
        <flow name="oas-example-console">
            <http:listener config-ref="oas-example-httpListenerConfig" path="/console/*">
                <http:response statusCode="#[vars.httpStatus default 200]">
                    <http:headers>#[vars.outboundHeaders default {}]</http:headers>
                </http:response>
                <http:error-response statusCode="#[vars.httpStatus default 500]">
                    <http:body>#[payload]</http:body>
                    <http:headers>#[vars.outboundHeaders default {}]</http:headers>
                </http:error-response>
            </http:listener>
            <apikit:console config-ref="oas-example-config" />
            <error-handler>
                <on-error-propagate type="APIKIT:NOT_FOUND">
                    <ee:transform doc:name="Transform Message">
                        <ee:message>
                            <ee:set-payload><![CDATA[%dw 2.0
    output application/json
    ---
    {message: "Resource not found"}]]></ee:set-payload>
                        </ee:message>
                        <ee:variables>
                            <ee:set-variable variableName="httpStatus">404</ee:set-variable>
                        </ee:variables>
                    </ee:transform>
                </on-error-propagate>
            </error-handler>
        </flow>
    ```

5.  Review the automatically generated Error Handler components.

    Example Error Handler Component

    ```xml
    <apikit:console config-ref="oas-example-config" />
        <error-handler>
            <on-error-propagate type="APIKIT:NOT_FOUND">
                <ee:transform doc:name="Transform Message">
                    <ee:message>
                        <ee:set-payload><![CDATA[%dw 2.0
    output application/json
    ---
    {message: "Resource not found"}]]></ee:set-payload>
                    </ee:message>
                    <ee:variables>
                        <ee:set-variable variableName="httpStatus">404</ee:set-variable>
                    </ee:variables>
                </ee:transform>
            </on-error-propagate>
        </error-handler>
    ```

## Name Your Interface and Implementation Files

When you import an API spec into an existing integration, Anypoint Code Builder automatically names
the configuration XML file based on the API spec name. You can change the file names to something
more descriptive, such as based on their function, for example:

- `interface.xml` receives all incoming requests to your application and scaffolded flows validate
  and route requests.

- `implementation.xml` provides the backend logic for calls to the interface.

To rename a file, right-click on the file, select **Rename**, and provide a new name.

## See Also

- [Creating Integrations](https://docs.mulesoft.com/anypoint-code-builder/int-create-integrations)

- [Iteratively Design and Implement APIs](https://docs.mulesoft.com/anypoint-code-builder/imp-implement-local-apis)

- [Implement a GraphQL API](https://docs.mulesoft.com/anypoint-code-builder/tut-graphql-implement-api)