A small but important honesty pass on the OpenAI-compatible API surface.

What changed

/v1/audio/speech and /v1/audio/transcriptions are part of the OpenAI-compatible spec and are wired in our router. They previously forwarded to the underlying provider router even when no model supporting that mode was registered, which produced confusing upstream errors.

These two endpoints now return a clean HTTP 501 endpoint_not_yet_available until at least one model supporting that capability is registered in our router. Response body:

{
  "detail": {
    "error": "endpoint_not_yet_available",
    "endpoint": "/v1/audio/speech",
    "capability": "audio_speech",
    "message": "/v1/audio/speech is not yet available on nRouter — no model supporting 'audio_speech' is currently registered. Roadmap: https://nrouter.ai/changelog",
    "available_endpoints": [
      "/v1/chat/completions",
      "/v1/completions",
      "/v1/embeddings",
      "/v1/images/generations",
      "/v1/videos"
    ]
  }
}

The gate is dynamic — the moment we register a model with the matching capability (e.g. a Whisper deployment for audio_transcription), the endpoint auto-unblocks at the next 30-second cache tick. No code change, no redeploy.

Live today

The endpoints below are fully supported by the Google Vertex AI models we ship on day one:

Endpoint	Models
`/v1/chat/completions`	Gemini 2.5 Pro / Flash / Flash-Lite / Flash-Image
`/v1/completions`	(legacy alias of chat completions)
`/v1/embeddings`	gemini-embedding-001, text-embedding-004 / 005, text-multilingual-embedding-002, multimodalembedding@001
`/v1/images/generations`	Imagen 3 / 4 (Fast, Standard, Ultra)
`/v1/videos`	Veo 3.1 (Fast, Standard, Lite)
`/v1/models`	catalogue lookup

Roadmap

Each capability below ships as soon as we land a provider integration that supports it:

audio_speech (TTS) — landing with OpenAI Direct
audio_transcription (STT / Whisper) — landing with OpenAI Direct

Track at /changelog.

Discoverability — new endpoint

GET /capabilities (authenticated) returns a machine-readable map of which endpoints are live right now, so SDKs and integrations can degrade gracefully:

curl https://api.nrouter.ai/capabilities \
  -H "Authorization: Bearer $NROUTER_API_KEY"

{
  "endpoints": {
    "/v1/chat/completions": { "available": true },
    "/v1/embeddings":       { "available": true },
    "/v1/audio/speech":     { "available": false, "required_capability": "audio_speech" }
    // …
  },
  "supported_modes": ["chat", "embedding", "image_generation", "video"]
}

Why this matters

The promise of an OpenAI-compatible gateway is "your SDK works, our infrastructure handles the rest". An endpoint that exists on paper but returns a confusing 4xx when called violates that promise. A 501 with a roadmap pointer makes the contract explicit and gives integrations a clean control flow to handle the gap.