Retrieve Your FastGPT App ID
Every chat application on FastGPT has a unique App ID, a required identifier for all Chat API requests. You can locate your App ID directly in the URL of your app’s details page. The App ID appears as a dedicated path segment within this URL, as shown in the official documentation’s referenced screenshot.
Authentication Methods
FastGPT supports three primary authentication workflows for Chat API requests:
- Recommended Body Authentication: When calling the
chat/completionsendpoint, include your API key and the targetappIddirectly in the request body. This is the standard, fully supported authentication method. - OpenAI SDK Compatibility Authentication: For clients built to align with OpenAI's API specifications, use the
Authorizationheader formatted asBearer <apiKey>-<appId>. Important: the-<appId>suffix is only a transport compatibility layer and is not stored on the FastGPT platform. - Team Member Proxy Authentication: If you need to route requests through a specific team member, the team owner must enable the
authProxyflag when creating or editing the associated API key. The proxied team member must already have explicit permission to access the target application and its chat functionality.
API Endpoint Configuration & Troubleshooting
FastGPT offers two Chat API endpoint versions: v1 and v2. Version 2 was introduced in FastGPT 4.9.4, while version 1 is no longer actively maintained. If you encounter a 404 error when submitting API requests, verify your BaseUrl configuration: some client packages require appending /v1 to the base platform URL to correctly resolve the endpoint path.
Required Request Parameters
| Parameter | Usage Location | Mandatory/Optional | Official Notes |
|---|---|---|---|
appId | Request body | Mandatory | Unique identifier for the target chat application |
apiKey | Request header or request body | Mandatory | Valid FastGPT platform API key |
Authorization | Request header | Optional | Use Bearer <apiKey>-<appId> for OpenAI SDK compatibility; suffix not stored |
authProxy | Team API key settings | Optional (team-only) | Enable to proxy requests through a specific team member |
| BaseUrl | Client configuration | Optional | Append /v1 to resolve 404 endpoint errors |
Source: FastGPT official source
Applicability and version scope
Use this page for the documented API scenario. Confirm the FastGPT, dependency, API, and deployment versions in the official source before applying a change.
Safety guardrails
Use [REDACTED_CREDENTIAL] for credentials and private data. Confirm the documented environment and version before review.
Rollback guidance
Restore the prior technical-content authority snapshot. Restore saved configuration and data snapshots, then repeat the smallest verification scenario.