Preview deployment not created for a fork branch

Why fork pull requests and fork branches passed to the preview API do not produce preview deployments, and how maintainers can preview fork changes.

If a pull request opened from a fork shows no preview deployment link, this is expected behavior. The same is true if a call to the Trigger preview deployment endpoint with a fork branch fails. Mintlify does not build preview deployments from fork branches.

The Mintlify GitHub App must be installed on a repository to build a preview. The app is installed on your main repository, not on contributor forks, so it cannot read a fork or build a preview against it. This applies to both automatic pull request previews and previews triggered through the API. The branch value in an API request must exist in the repository connected to your Mintlify project.

Preview changes from a fork

A maintainer with write access to the main repository can push the fork's branch to the main repository, then open a pull request from that branch or pass that branch name to the API. See Fork pull requests for details.