> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://contentful.com/developers/docs/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://contentful.com/_mcp/server.

#### Currently supported actions:

* Query release asset versions
* Fetch release asset version
* Update release asset version

## Assets collection

[Get all assets of a release](/references/content-management-api/timeline-assets/get-all-assets-of-a-release)

To fetch specific assets use [query search parameters](/references/content-management-api/search-parameters).

[Create an asset](/references/content-management-api/timeline-assets/create-an-asset-in-a-release)

Use this endpoint to create a new asset and add it to the release in one step.

When using this endpoint, an ID will be automatically generated for the created asset and returned with the response.

## Asset

[Update an asset](/references/content-management-api/timeline-assets/update-an-asset)

Use this endpoint to create a new asset with a specified ID, or update an existing asset with its ID.

> **Info**
>
> When updating an existing asset, you need to specify the last version you have of the asset with `X-Contentful-Version`.

[Get an asset](/references/content-management-api/timeline-assets/get-an-asset-in-a-release)

## Asset processing

To publish an asset, or to preview it within the Contentful web app (under the "Media" tab), you need to process it before. This step is fetching the image from the given location to Contentful's system. This request might return before the asset processing is finished. The asset will have a `fields.file.url` for the respective locale if processing completed successfully.

Due to security considerations we forbid users to upload and process files with mime type `text/html` or `text/javascript`.

If you want to store HTML files in Contentful, please use `application/octet-stream` as the `contentType`. Keep in mind that these files will not be rendered by browsers by default.

[Process an asset](/references/content-management-api/timeline-assets/process-an-asset-in-a-release)


## API Docs

- Timeline assets [Get all assets of a release](https://contentful.com/developers/docs/references/content-management-api/timeline-assets/get-all-assets-of-a-release.md)
- Timeline assets [Create an asset in a release](https://contentful.com/developers/docs/references/content-management-api/timeline-assets/create-an-asset-in-a-release.md)
- Timeline assets [Get an asset in a release](https://contentful.com/developers/docs/references/content-management-api/timeline-assets/get-an-asset-in-a-release.md)
- Timeline assets [Update an asset](https://contentful.com/developers/docs/references/content-management-api/timeline-assets/update-an-asset.md)
- Timeline assets [Process an asset in a release](https://contentful.com/developers/docs/references/content-management-api/timeline-assets/process-an-asset-in-a-release.md)

## OpenAPI Specification

The raw OpenAPI 3.1 specification for this API is available at:
- [OpenAPI JSON](https://contentful.com/developers/docs/openapi.json)
- [OpenAPI YAML](https://contentful.com/developers/docs/openapi.yaml)