Switching AI providers looks simple in a demo and gets harder in production. The demo shows one successful call. It does not show what changes when traffic arrives, a request fails, or someone asks where the data went. This checklist covers the five areas a demo hides, in the order that matters.
1. Contract compatibility. Does the candidate mirror
the OpenAI surface you already call? Check the exact paths, the request
fields you depend on, and whether the response object matches. If you
only need POST /v1/chat/completions, compatibility is
usually a base URL and key change. If you also depend on transcription,
confirm POST /v1/audio/transcriptions and the response
formats you parse.
2. Request and response shape. Read the response schema, not just the happy path. Confirm streaming works if you stream, and that the finish reason, usage object and error shape are what your client expects. Send the same request twice, buffered and streamed. They should agree.
3. Cost model. Ask what the meter counts. Token input and output are the common case, but audio is often billed by duration. Write down the unit, the rate and what is included in your plan before you estimate a monthly number, then check the estimate against one week of real usage rather than a marketing page.
4. Limits and failure behavior. Find the rate limits and the concurrency ceiling, then decide what your client does at the boundary. Retries need a backoff and a cap. A second provider is only useful if you have already decided when to fall back to it, and how you will tell that it happened.
5. Data handling. Confirm where the request data goes, how long it is retained, and what the provider says about training on it. This is a review question, not a legal one. If the answer is unclear, that is the finding.
Work through the five and you have a go or a no-go with evidence, which is more useful than another demo. If one area stays open, that is usually the thing worth a short working session.