# Git Providers

Coder Agents leverages your existing
[external authentication](../../../admin/external-auth/index.md) configuration
to power the in-chat diff viewer.
Self-hosted GitHub Enterprise deployments require one additional setting
(`API_BASE_URL`) for this feature to work.

## GitHub Enterprise configuration

For public `github.com`, no additional configuration is needed.

For self-hosted GitHub Enterprise, add `API_BASE_URL` to your
[existing configuration](../../../admin/external-auth/index.md#github-enterprise):

```env
CODER_EXTERNAL_AUTH_0_ID="primary-github"
CODER_EXTERNAL_AUTH_0_TYPE=github
CODER_EXTERNAL_AUTH_0_CLIENT_ID=xxxxxx
CODER_EXTERNAL_AUTH_0_CLIENT_SECRET=xxxxxxx
CODER_EXTERNAL_AUTH_0_AUTH_URL="https://github.example.com/login/oauth/authorize"
CODER_EXTERNAL_AUTH_0_TOKEN_URL="https://github.example.com/login/oauth/access_token"
CODER_EXTERNAL_AUTH_0_VALIDATE_URL="https://github.example.com/api/v3/user"
CODER_EXTERNAL_AUTH_0_API_BASE_URL="https://github.example.com/api/v3"
CODER_EXTERNAL_AUTH_0_REGEX=github\.example\.com
```

Without `API_BASE_URL`, Coder defaults to `https://api.github.com`. Clone
and push still work (they use `AUTH_URL` and `TOKEN_URL` directly), but
the diff viewer silently fails because Coder builds its URL-matching
patterns from the API base URL.

> [!NOTE]
> If you have both a `github.com` and a GHE external auth config, only the
> GHE config needs `API_BASE_URL`.

## GitLab configuration

For `gitlab.com`, no additional `API_BASE_URL` is needed. Coder
automatically derives it from your `AUTH_URL` for self-hosted instances.

### Required scopes

The default GitLab scopes (`read_user`) are sufficient for basic
authentication. To use merge request features (diffs, status checks) with
Coder Agents, configure:

```env
CODER_EXTERNAL_AUTH_0_ID="primary-gitlab"
CODER_EXTERNAL_AUTH_0_TYPE=gitlab
CODER_EXTERNAL_AUTH_0_CLIENT_ID=xxxxxx
CODER_EXTERNAL_AUTH_0_CLIENT_SECRET=xxxxxxx
CODER_EXTERNAL_AUTH_0_SCOPES="write_repository read_api"
```

The `read_api` scope grants read access to the API (needed for fetching
merge request metadata and diffs). The `write_repository` scope allows
pushing commits and creating merge requests.

### Self-hosted GitLab

For self-hosted GitLab, set `AUTH_URL` and `TOKEN_URL` to your instance.
Coder derives `API_BASE_URL` automatically from `AUTH_URL`:

```env
CODER_EXTERNAL_AUTH_0_ID="primary-gitlab"
CODER_EXTERNAL_AUTH_0_TYPE=gitlab
CODER_EXTERNAL_AUTH_0_CLIENT_ID=xxxxxx
CODER_EXTERNAL_AUTH_0_CLIENT_SECRET=xxxxxxx
CODER_EXTERNAL_AUTH_0_AUTH_URL="https://gitlab.example.com/oauth/authorize"
CODER_EXTERNAL_AUTH_0_TOKEN_URL="https://gitlab.example.com/oauth/token"
CODER_EXTERNAL_AUTH_0_SCOPES="write_repository read_api"
CODER_EXTERNAL_AUTH_0_REGEX=gitlab\.example\.com
```

> [!NOTE]
> You may also set `API_BASE_URL` explicitly if needed (e.g.,
> `https://gitlab.example.com/api/v4`), but this is usually unnecessary.

## Known limitations

### GitLab

The GitLab provider has some semantic differences compared to the GitHub
provider:

- **Approved** uses GitLab's threshold-based approval (e.g., "all required
  approvals met") rather than GitHub's "at least one approval and no changes
  requested" model.
- **Changes requested** has no GitLab equivalent. This field is always
  reported as `false`.
- **Reviewer count** only counts users who have approved, not all assigned
  reviewers.

These gaps are tracked internally and may be refined in future releases.

## Troubleshooting

### Diffs not appearing on GHE

Add `API_BASE_URL` to your GHE external auth config and restart Coder.
Diffs should appear within a couple of minutes.

### Users not seeing diffs

The chat owner must have linked their account through the relevant external
auth provider.

### Checking logs

Look for gitsync warnings such as `no provider for origin` or
`resolve token` errors.