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The system does not apply any rate limits for server-to-server API calls. Instead, the system aims to grow with the business to handle the throughput needs required. That said, certain rate limits are applied on browser/app-to-server API calls in order to prevent enumeration attacks, preventing a malicious party from enumerating credit, debit, or scheme cards to check their validity.

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Enumeration prevention

To prevent enumeration attacks, the following limits are applied.
Rate limitThe current rate limit for these endpoints is set to approximately 50 requests per minute across all endpoints, per token. This value may be adjusted downward in time to adjust for enumeration attacks.Generating a new checkout session ID or JWT token for every checkout is recommended to prevent a user from being rate-limited.
When a token or checkout session exceeds the limit, the API returns a 429 response with a Retry-After header that holds the number of seconds to wait before you retry.

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Traffic peaks

There’s no fixed request quota for server-to-server API calls. Capacity scales automatically with your traffic. During a very sudden spike, some requests can be slower or return a 429 response while capacity scales up.
  • Retry 429 responses with an exponential back-off, and send an Idempotency-Key on requests that support it so a retry can’t create a duplicate.
  • Tell support about planned peaks, such as a sale or a seasonal event, ahead of time. Include the dates and the volume you expect so capacity can be raised in advance.