**You pay for GPT-5, but you may be getting something else.**
A relay or reseller gateway can switch your request to a cheaper model and still return a convincing response—unless you verify it.
Ask any relay, not just ours The testing API is open for external use, so you can use it to check other services you rely on.
Look at model fingerprints, not self-reported identity A model’s answer to “Who are you?” isn’t reliable; the test compares behavioral signatures.
Feed results into your monitoring Schedule calls and wire scores into alerts.
Tested over 5,000 different endpoints more than 30,000 times covering 440+ models. Run it on your own endpoint and see.
Your agent has been live for three months. Costs haven’t changed, but quality has quietly slipped. You suspect the upstream changed models, but you have no evidence—the support team only says, “The model hasn’t changed.” Sample the same endpoint repeatedly through the testing API, and you get data you can put in front of the team.