# OpenAPI specification
> Source: https://docs.strapi.io/cms/api/openapi
Strapi provides a CLI tool to automatically generate OpenAPI 3.1.0 specifications documenting all API endpoints, parameters, and responses. The generated specification can be integrated with Swagger UI for interactive API documentation.
Strapi provides a command-line tool to generate [OpenAPI](https://www.openapis.org/) specifications for your applications.
The CLI tool automatically creates comprehensive API documentation that describes all available endpoints, parameters, and response formats in your Strapi application's Content API. Among the possible use cases, the generated specification can then be easily integrated into documentation tools like [Swagger UI ](https://swagger.io/tools/swagger-ui/).
:::callout 🚧 Experimental feature
The OpenAPI generation feature is currently experimental. Its behavior and output might change in future releases without following semantic versioning. For additional information and context, please refer to the [Strapi Contributor Docs ](https://contributor.strapi.io/openapi).
:::
## Generating an OpenAPI specification
The OpenAPI generation tool is included with Strapi core and doesn't require additional installation. You can use it directly from the command line in any Strapi project to generate comprehensive API documentation.
:::note Known limitation for nested component `required` metadata
The Admin panel can mark inner fields on a component as required, yet the generated OpenAPI file may still skip a `required` entry for those scalars. The parent object (for instance a component inside a dynamic zone) might list `required` while the nested properties do not. There is more background in [GitHub issue #2236](https://github.com/strapi/documentation/issues/2236). Client generators that trust the raw schema alone can therefore emit types that look looser than what Strapi actually enforces.
This area is still experimental, same as the warning banner at the top of the page, so keep validating nested payloads in application code or with the [REST validation helpers](/cms/backend-customization/controllers#sanitization-and-validation-in-controllers) from the controllers guide instead of assuming every Admin rule is mirrored in the exported JSON schema yet.
:::
### CLI usage
Executing the command without any arguments will generate a `specification.json` file at the root of your Strapi folder project:
```shell
yarn strapi openapi generate
```
```shell
npm run strapi openapi generate
```
You can also path an optional `--output` argument to specify the path and filename, as in the following example:
```bash
yarn strapi openapi generate --output ./docs/api-spec.json
```
```bash
npm run strapi openapi generate -- --output ./docs/api-spec.json
```
### Specification structure and content
The generated OpenAPI specification follows the [OpenAPI 3.1.0 standard](https://spec.openapis.org/oas/v3.1.0.html) and could look like in the following shortened example:
```json
{
"openapi": "3.1.0",
"x-powered-by": "strapi",
"x-strapi-version": "5.21.0",
"info": {
"title": "My Strapi API",
"description": "API documentation for My Strapi API",
"version": "1.0.0"
},
"paths": {
"/api/articles": {
"get": {
"operationId": "article/get/articles",
"parameters": [
{
"name": "fields",
"in": "query",
"schema": {
"type": "array",
"items": { "type": "string" }
}
}
],
"responses": {
"200": {
"description": "Successful response",
"content": {
"application/json": {
"schema": {
"type": "object",
"properties": {
"data": {
"type": "array",
"items": { "$ref": "#/components/schemas/Article" }
}
}
}
}
}
}
}
}
}
},
"components": {
"schemas": {
"Article": {
"type": "object",
"properties": {
"id": { "type": "string" },
"title": { "type": "string" },
"content": { "type": "string" }
}
}
}
}
}
```
The generated OpenAPI specification includes all available API endpoints in your Strapi application, and information about these endpoints, such as the following:
- CRUD operations for all content types
- Custom API routes defined in your application
- Authentication endpoints for user management
- File upload endpoints for media handling
- Plugin endpoints from installed plugins
## Integrating with Swagger UI
With the following steps you can quickly generate a [Swagger UI](https://swagger.io/)-compatible page:
1. Generate a specification:
```bash
yarn strapi openapi generate --output ./public/swagger-spec.json
```
```bash
npm run strapi openapi generate -- --output ./public/swagger-spec.json
```
2. Update [the `/config/middlewares.js` configuration file](/cms/configurations/middlewares) with the following code:
```js title="/config/middlewares.js"
module.exports = [
'strapi::logger',
'strapi::errors',
{
name: 'strapi::security',
config: {
contentSecurityPolicy: {
useDefaults: true,
directives: {
'script-src': ["'self'", "'unsafe-inline'", 'https://unpkg.com'],
'style-src': ["'self'", "'unsafe-inline'", 'https://unpkg.com'],
'connect-src': ["'self'", 'https:'],
'img-src': ["'self'", 'data:', 'blob:', 'https:'],
'media-src': ["'self'", 'data:', 'blob:'],
upgradeInsecureRequests: null,
},
},
},
},
'strapi::cors',
'strapi::poweredBy',
'strapi::query',
'strapi::body',
'strapi::session',
'strapi::favicon',
'strapi::public',
];
```
```js title="/config/middlewares.ts"
export default [
'strapi::logger',
'strapi::errors',
{
name: 'strapi::security',
config: {
contentSecurityPolicy: {
useDefaults: true,
directives: {
'script-src': ["'self'", "'unsafe-inline'", 'https://unpkg.com'],
'style-src': ["'self'", "'unsafe-inline'", 'https://unpkg.com'],
'connect-src': ["'self'", 'https:'],
'img-src': ["'self'", 'data:', 'blob:', 'https:'],
'media-src': ["'self'", 'data:', 'blob:'],
upgradeInsecureRequests: null,
},
},
},
},
'strapi::cors',
'strapi::poweredBy',
'strapi::query',
'strapi::body',
'strapi::session',
'strapi::favicon',
'strapi::public',
];
```
This will ensure the Swagger UI display from [unpkg.com](https://unpkg.com/) is not blocked by Strapi's CSP policy handled by the [security middleware](/cms/configurations/middlewares#security).
3. Create a `public/openapi.html` file in your Strapi project to display the Swagger UI, with the following code:
```html
API Documentation
```
4. Restart the Strapi server with `yarn develop` or `npm run develop` and visit the `/openapi.html` page. The Swagger UI should be displayed:
