Build

Streaming

Server-sent events, unbuffered end to end. The last chunk before [DONE] tells you exactly what the request cost.

A streaming request

curl -N https://api.minirouter.sh/v1/chat/completions \
  -H "Authorization: Bearer $MINIROUTER_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "meta/llama-3.3-70b",
    "messages": [{"role":"user","content":"ping"}],
    "stream": true
  }'

Set "stream": true and read SSE chunks until data: [DONE]. Chunks arrive as the model generates them.

The cost trailer

The final chunk before [DONE] carries the usage object, including usage.cost, the exact USD charge:

Final chunks of a stream

data: {"id":"chatcmpl-...","choices":[{"delta":{},"finish_reason":"stop","index":0}],
       "usage":{"prompt_tokens":12480,"completion_tokens":902,
                "total_tokens":13382,"cost":0.0412}}

data: [DONE]

Non-streaming responses carry the same field and the x-minirouter-cost-usd header. Streaming responses include these headers:

Header	Meaning
x-minirouter-provider	The upstream that actually served it.
x-minirouter-ttft-ms	Time to first token, in milliseconds.
x-minirouter-balance-usd	Your available balance at the start of the stream, after its hold. Read the final charge in usage.cost in the last usage chunk.

Aborting a stream

When your client closes the socket we abort the upstream immediately. You are charged for the tokens generated before the abort. A stream the upstream kills before 50 output tokens is written off entirely.

Mid-stream exhaustion

If your balance reaches $0 mid-stream, the stream ends with an OpenAI-shaped error chunk, then [DONE], then a clean close. Never a silent socket close:

Terminal exhaustion chunk

data: {"error":{"message":"Insufficient credits: this response stopped because
       your balance reached $0. You were charged $0.0031 for the tokens
       delivered. Top up at https://minirouter.sh/dashboard/billing",
       "type":"invalid_request_error","code":"insufficient_credits"}}

data: [DONE]

Details under insufficient_credits. The x-minirouter-balance-usd header is on every response so your tooling can warn first.

Retries and the first byte

Before the first content byte we retry on another upstream automatically. After it, we cannot. See failover.