Decoding GPT API Rate Limits: Understanding Tier Levels and Testing Strategies

Developers frequently encounter 429 rate limit errors in production but struggle to identify which specific limit (TPM, RPM, daily tokens) they've exceeded. OpenAI's rate limits vary significantly by model, tier level, and account spending, requiring careful diagnosis before scaling. Using tools like Apidog to inspect API response headers and run load tests enables teams to validate rate limits and implement proper mitigation strategies before deploying to production.