@asyncapi/generator/docs/configuration-file.md

The AsyncAPI generator. It can generate documentation, code, anything!

---
title: "Configuration file"
weight: 90
---

You can configure your AsyncAPI Generator template using either a dedicated `.ageneratorrc` YAML file or through the `generator` property in your `package.json` file. Previously, generator configuration had to be defined in the `package.json` file. Now, you can define the configuration in a separate `.ageneratorrc` file. The configuration defined in the `.ageneratorrc` file will override any configuration defined in `package.json`. The generator will first check for the `.ageneratorrc` file in the template's root directory, and if not found, it will look for the generator config in `package.json`.

> **Note:** The `metadata` object is **required** for all baked-in templates (templates developed and shipped as part of the Generator repository) and is used by the generator’s build system to index, categorize, and load these templates.  
> The `metadata` section is **not used or required** for standalone templates (external npm packages or repositories).

## Configuration methods

### Option 1: using `.ageneratorrc` file (Recommended)

Create a `.ageneratorrc` file in the root of your template with YAML syntax. This approach keeps your template configuration separate from package metadata:

```yaml
metadata:
  type: client
  protocol: websocket
  target: javascript
  stack: express

apiVersion: v3
supportedProtocols:
  - amqp
  - mqtt

parameters:
  server:
    description: The server you want to use in the code.
    required: true
  dummyParameter:
    description: Example of parameter with default value.
    default: just a string
    required: false

conditionalFiles:
  path/to/file/that/is/relative/to/template/dir/test-amqp.js:
    subject: server.protocol
    validation:
      const: amqp
  path/to/file/that/is/relative/to/template/dir/support.html:
    subject: info.contact
    validation:
      required:
        - url

conditionalGeneration:
  conditionalOnFile.js:
    parameter: singleFile
    validation:
      not:
        const: true
  conditionOnFolderInfo:
    subject: info.contact.name
    validation:
      const: API Support

nonRenderableFiles:
  - src/api/middlewares/*.*
  - lib/lib/config.js

generator: "<2.0.0"

filters:
  - my-package-with-filters

hooks:
  '@asyncapi/generator-hooks': hookFunctionName
  my-custom-hooks-package:
    - myHook
    - andAnotherOne
```

### Option 2: using `package.json`

Alternatively, you can include your configuration in the `generator` property of your `package.json` file:

```json
"generator": {
  "metadata": {
    "type": "client",
    "protocol": "websocket",
    "target": "javascript",
    "stack": "express"
  },
  "apiVersion": "v3",
  "supportedProtocols": ["amqp", "mqtt"],
  "parameters": {
    "server": {
      "description": "The server you want to use in the code.",
      "required": true
    },
    "dummyParameter": {
      "description": "Example of parameter with default value.",
      "default": "just a string",
      "required": false
    }
  },
  "conditionalGeneration": {
     "conditionalOnFile.js": { 
       "parameter": "singleFile", 
       "validation": {
          "not": { "const": "true" } 
      }
    },
     "conditionOnFolder": {
       "parameter": "singleFolder", 
       "validation": {
          "not": { "const": "true" } 
      }
    },
     "conditionOnFolderInfo": {
       "subject": "info.contact.name",
       "validation": {
            "const": "API Support"
        }
    }
  },
  "nonRenderableFiles": [
    "src/api/middlewares/*.*",
    "lib/lib/config.js"
  ],
  "generator": "<2.0.0",
  "filters": [
    "my-package-with-filters"
  ],
  "hooks": {
    "@asyncapi/generator-hooks": "hookFunctionName",
    "my-custom-hooks-package": ["myHook", "andAnotherOne"]
  }
}
```

> **Note:** If both `.ageneratorrc` file and the `generator` property in `package.json` exist, the configuration from `.ageneratorrc` will override the `package.json` configuration.

## Configuration options reference

The following table describes all available configuration options for templates.

The `generator` property from `package.json` file must contain a JSON object and the `ageneratorrc` file must contain a YAML object that may have the following information:

| Name | Type | Description |
|------|------|-------------|
| `metadata` | Object | **(Required for baked-in templates)**. Template identification and classification. Contains `type`, `protocol`, `target`, and optional `stack`. See below. |
| `metadata.type` | String | **Required**. The type of template. Allowed values: `client`, `sdk`, `docs`, `config`. |
| `metadata.protocol` | String | **Required for `client`/`sdk`**. The protocol this template targets (e.g., `websocket`, `kafka`). Not used for `docs`/`config`. |
| `metadata.target` | String | **Required**. The output language or format (e.g., `javascript`, `html`, `yaml`). |
| `metadata.stack` | String | Optional. The stack or framework (e.g., `express`, `quarkus`). Only for `client`/`sdk`. |
| `apiVersion` | String | Determines which **major** version of the [Parser-API](https://github.com/asyncapi/parser-api) the template uses. For example, `v2` for `v2.x.x`. If not specified, the Generator assumes the template is not compatible with the Parser-API so it will use the [Parser-JS v1 API](https://github.com/asyncapi/parser-js/tree/v1.18.1#api-documentation). For templates that need to support AsyncAPI specification v3 make sure to use `v3` [Parser-API](https://github.com/asyncapi/parser-api). If the template uses a version of the Parser-API that is not supported by the Generator, the Generator will throw an error. |
| `supportedProtocols` | [String] | A list with all the protocols this template supports. |
| `parameters` | Object[String, Object] | An object with all the parameters that can be passed when generating the template. When using the command line, it's done by indicating `--param name=value` or `-p name=value`. |
| `parameters[param].description` | String | A user-friendly description about the parameter. |
| `parameters[param].default` | Any | Default value of the parameter if not specified. Shouldn't be used for mandatory `required=true` parameters. |
| `parameters[param].required` | Boolean | Whether the parameter is required or not. |
| `conditionalFiles` | Object[String, Object] | An object containing all the file paths that should be conditionally rendered. Each key represents a file path and each value must be an object with the keys `subject` and `validation`. The file path should be relative to the `template` directory inside the template. **Note: It is deprecated and will be removed with future releases. Use `conditionalGeneration` instead.** |
| `conditionalFiles[filePath].subject` | String | The `subject` is a [JMESPath](http://jmespath.org/) query to grab the value you want to apply the condition to. It queries an object with the whole AsyncAPI document and, when specified, the given server. The object looks like this: `{ asyncapi: { ... }, server: { ... } }`. If the template supports the `server` parameter, you can access server details, for example, `server.protocol`. During validation with `conditionalFiles`, only the server that the template user selected is available in the specification file. For more information about `server` parameter [read about special parameters](#special-parameters). **Note: It is deprecated and will be removed with future releases. Use `conditionalGeneration` instead.** |
| `conditionalFiles[filePath].validation` | Object | The `validation` is a JSON Schema Draft 07 object. This JSON Schema definition will be applied to the JSON value resulting from the `subject` query. If validation doesn't have errors, the condition is met, and therefore the given file will be rendered. Otherwise, the file is ignored. Check [JSON Schema Validation](https://json-schema.org/draft-07/json-schema-validation.html#rfc.section.6) for a list of all possible validation keywords. **Note: It is deprecated and will be removed with future releases. Use `conditionalGeneration` instead.** |
| `conditionalGeneration` | Object[String, `{ subject?: String, parameter?: String, validation: Object }`] | An object containing all the file paths or directory names that should be conditionally rendered. Each key represents a file path or directory name and each value must be an object with the keys `subject`, `parameter` and `validation`. You can use either subject or parameter according to the use case. The path should be relative to the `template` directory inside the template. **Note: conditionalGeneration and conditionalFile are mutually exclusive, which means both cannot be configured at the same time in the template**. |
| `conditionalGeneration[filePath/directoryName].subject` | String | The `subject` is a [JMESPath](http://jmespath.org/) query to grab the value you want to apply the condition to. It queries an object with the whole AsyncAPI document and, when specified, the given server. The object looks like this: `{ asyncapi: { ... }, server: { ... } }`. If the template supports the `server` parameter, you can access server details like, for example, protocol this way: `server.protocol`. During validation with `conditionalGeneration`, only the server that the template user selected is available in the specification file. For more information about the `server` parameter [read about special parameters](#special-parameters). |
| `conditionalGeneration[filePath/directoryName].parameter` | String | The `parameter` is the name of a custom template parameter passed through `templateParams` that controls whether a specific file or folder should be included in the generated output. You must define a `validation` rule using a JSON Schema fragment to apply the condition. For example, if you define `"parameter": "includeDocs"` with `"validation": { "const": true }`, the corresponding folder (e.g., `docs/`) will only be generated when the user passes `{ includeDocs: true }`. If `includeDocs` is `false`, it will be skipped. When you rely on a parameter here, make sure its default value declared in the `parameters` section uses the same data type your validation expects; mismatched types lead to failing conditions even when the defaults should allow generation. |
| `conditionalGeneration[filePath/directoryName].validation` | Object (JSON Schema fragment) | The validation defines the condition under which the file or directory will be generated. It must be a valid JSON Schema fragment that validates the value of the parameter. For example, if you want to include a folder only when includeDocs is true, use "validation": `{ "const": true }`. You can also use more complex validation logic, like "enum": ["yes", "true"] or "type": "string" with a "pattern" constraint. If the parameter fails validation, the file or folder will not be included in the generated output. This allows for powerful and flexible control over template generation based on user input. |
| `nonRenderableFiles` | [String] | A list of file paths or [globs](https://en.wikipedia.org/wiki/Glob_(programming)) that must be copied "as-is" to the target directory, i.e., without performing any rendering process. This is useful when you want to copy binary files. |
| `generator` | [String] | A string representing the generator version-range the template is compatible with. This value must follow the [semver](https://nodejs.dev/learn/semantic-versioning-using-npm) syntax. E.g., `>=1.0.0`, `>=1.0.0 <=2.0.0`, `~1.0.0`, `^1.0.0`, `1.0.0`, etc. [Read more about semver](https://docs.npmjs.com/about-semantic-versioning). |
| `hooks` | Object[String, String] or Object[String, Array[String]] | A list of modules containing hooks, except for the ones you keep locally in your template in the default location. For each module you must specify the exact name of the hook that should be used in the template. For a single hook, you can specify it as a string; for more hooks, you must pass an array of strings. In the case of external modules, remember they need to be added as a dependency in `package.json` of your template. There is also [an official hooks library](hooks#official-library) always included in the generator. As this is a library of multiple hooks, you still need to explicitly specify in the configuration which one you want to use. Use `@asyncapi/generator-hooks` as the library name. |

## Special parameters

There are some template parameters that have a special meaning:

| Name | Description |
|------|-------------|
| `server` | It is used to let the template know which server from the AsyncAPI specification file you want to use. In some cases, this may be required. For instance, when generating code that connects to a specific server. Use this parameter in case your template relies on users' information about what server from the specification file they want to use during generation. You also need this parameter if you want to use `server.protocol` notation within `conditionalGeneration` configuration option. Once you decide to specify this parameter for your template, it is recommended you make it a mandatory parameter otherwise a feature like `conditionalGeneration` is not going to work if your users do not use this parameter obligatory.