API Endpoints
Most clients need an API address (base URL) during setup. Flux exposes three entry points, one per protocol format.
Protocol Entry Points
| Protocol format | Base URL | Typical request path |
|---|---|---|
| OpenAI format | https://api.tryflux.net/v1 | POST /chat/completions or POST /responses |
| Anthropic format | https://api.tryflux.net | POST /v1/messages |
| Gemini format | https://api.tryflux.net | POST /v1beta/models/<model-id>:generateContent |
The OpenAI and Anthropic endpoints can also be copied directly from the top of the API keys page.
Which Format to Use
The client dictates the format, and the group must support that same format.
| Format | Clients |
|---|---|
OpenAI format (ends with /v1) | Cherry Studio, RikkaHub, OpenCode, and anything labelled "OpenAI compatible" |
Anthropic format (no /v1) | Claude Code and other clients speaking the Anthropic protocol natively |
| Gemini format | Clients and SDKs on Google's native protocol, where the model ID goes in the request path |
If the client's setting is named ANTHROPIC_BASE_URL, use the Anthropic format. If it is OPENAI_BASE_URL, use the OpenAI format. Base URL is a generic field name and does not identify a protocol; check the selected provider type first. Each integration guide states the exact value.
The OpenAI format includes distinct APIs such as Chat Completions and Responses; Codex uses Responses, for example. Sharing a base URL does not mean a model supports every API. Check that the group and model support the requests your client sends. Complete test requests are in Troubleshooting.
Authentication
The API key is sent in a request header, which most clients handle automatically.
| Entry point | Accepted credentials |
|---|---|
| OpenAI format, Anthropic format | Authorization: Bearer <key>, x-api-key: <key>, x-goog-api-key: <key> |
| Gemini format | All of the above, plus the query parameter ?key=<key> |
The OpenAI and Anthropic formats do not accept a key in the query string and return 400. On the Gemini format, ?api_key= is deprecated; use ?key= or a header.
With a composite key, the model ID needs a prefix; on the Gemini format the prefix goes in the path.
Related Pages
- Create API Key - get a key first
- Quickstart - pick an integration path by client
- Troubleshooting - what to check when a client cannot connect
- Error Codes - the full list of authentication and request errors