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To maintain system reliability and provide a fair experience across users, Antei enforces strict rate limits across its API. These limits vary slightly between the Live and Sandbox environments.

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Live Environment Limits

These limits apply per API key, Org, User, IP Address, across all paid plans.

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Sandbox Environment Limits

Sandbox is intended for testing and development. It enforces tighter limits to simulate real-world constraints and prevent abuse.

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Response Headers

Each API response returns rate limit headers so you can monitor usage:
Response

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Exceeding Limits

When you exceed the limit:
  • You’ll receive a 429 Too Many Requests error
  • The response will include a helpful message
  • Headers will guide retry timing
Retry-After headers may be included to indicate how long to wait before retrying.

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Best Practices

Cache tax results wherever possible
Use exponential backoff on 429 errors
Monitor rate limit headers programmatically

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Need More?

For higher throughput or enterprise needs, contact support@antei.com with your expected volume and use case.