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Create chat completion

POST/v1/chat/completions

Direct proxy to the upstream provider's OpenAI-compatible chat completions endpoint. The request body is forwarded as-is — every field your chosen model supports passes through unmodified.

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Request body

model

required, string — a catalog id from GET /v1/models

messages

required, array — standard OpenAI message list

stream

optional, boolean — SSE token deltas when true

max_tokens

optional, number — capped server-side to what your balance can cover

…

any other field the target model supports (temperature, tools, response_format, reasoning_effort, …) is forwarded unmodified

cURL example

terminal

curl https://apily.pro/v1/chat/completions \
  -H "Authorization: Bearer apily_your-api-key" \
  -H "Content-Type: application/json" \
  -d '{"model":"gpt-5.6-sol","messages":[{"role":"user","content":"ping"}]}'

Response

Mirrors the upstream provider's OpenAI-compatible response verbatim — a choices array and a usage object (prompt_tokens, completion_tokens, plus cache token fields when the model supports them). Streaming requests get the same shape split into SSE chunks, ending with data: [DONE].

Error responses

Symptom	Cause	Fix
`401 Missing API key`	No auth header was sent.	Apily accepts `Authorization: Bearer …` and `x-api-key: …`.
`401 Invalid API key`	Key copied with stray spaces, truncated, or revoked.	Copy the key whole from the API page in your Apily account, the `apily_` prefix included.
`403 Email not verified`	Your Apily account's email address isn't verified yet.	Verify your email from the banner in the Apily app, then retry.
`404 Model not found`	The model ID isn't in the Apily catalog.	Copy the exact ID from `GET /v1/models` or the Models page in your account.
`503 Model temporarily unavailable`	The model exists, but no upstream provider is reachable right now.	Retry in a moment — it usually recovers within a minute. Switch models if it keeps happening.
`402 Insufficient balance`	Your token balance can't cover the request's estimated cost.	Top up your balance on the Billing page in your Apily account.
`429 Too many requests`	Your account sent more than 600 `/v1/*` requests in a minute — all of your API keys share one budget. The body is `{ error: { message, type: "rate_limit_error", code: "rate_limit_exceeded" }, retryAfterSeconds }`.	Wait the `Retry-After` header (or `retryAfterSeconds`) before retrying, and lower request concurrency.
`502 Upstream error`	The upstream provider returned an unexpected error.	Retry the request; try a different model if it persists.