Rate limiting is used by the API to prevent abuse and ensure a reliable experience for all consumers. The current limit for the public API is approximately 3 Requests Per Second (RPS)/40 Requests Per Minute (RPM) with a short burst of up to 5 times allowed. Note that the rate limits listed above are only approximations. The rate limit per chain is throttled, which means it can be variable, not just per chain, but potentially per call; however, these rates are generally sufficient for public use.
This API is intended for public use. If you are an integrator who needs access higher rate limits, please fill out the 0x API Taker Integration Request Form.