How do you update or change your rate limit headers without breaking your existing API contracts?

1 Use standard headers

One of the first steps to ensure a smooth transition is to use standard headers for your rate limit information. The most common headers are X-Rate-Limit-Limit, X-Rate-Limit-Remaining, and X-Rate-Limit-Reset, which indicate the maximum number of requests, the remaining number of requests, and the time when the limit will be reset, respectively. These headers are widely recognized and supported by many libraries and tools, and they can help you avoid naming conflicts or ambiguities with other headers. If you use these headers, you can also leverage existing documentation and examples to explain your rate limit policy to your clients.

3 Implement backwards compatibility

A third step is to implement backwards compatibility for your rate limit headers, if possible. This means that you should try to keep the old headers working alongside the new ones, at least for a grace period, to give your clients enough time to adjust. For example, if you change the header name from X-Rate-Limit-Limit to RateLimit-Limit, you can still send both headers with the same value for a while, until you phase out the old one. Alternatively, if you change the header value from seconds to milliseconds, you can send both values with different units, such as X-Rate-Limit-Reset: 60 and X-Rate-Limit-Reset-Ms: 60000. This way, you can avoid breaking the existing functionality or logic of your clients.

4 Validate and monitor changes

A fourth step is to validate and monitor the changes in your rate limit headers, before and after deploying them. You should test your API with different scenarios and clients, and check if the headers are sent and received correctly. You should also monitor the performance and usage of your API, and look for any anomalies or issues that might indicate a problem with the rate limit headers. You can use tools like Postman, Curl, or API testing frameworks to validate your headers, and tools like Google Analytics, Prometheus, or API management platforms to monitor your API. By doing this, you can ensure that your changes are working as intended, and fix any bugs or errors quickly.

6 Follow best practices

A sixth and final step is to follow best practices for rate limiting in general, regardless of the changes in your headers. To ensure a robust and reliable API that serves your clients well, it is important to use a fair and reasonable rate limit policy that balances availability and security with customer expectations. Additionally, document your rate limit policy clearly and comprehensively, providing helpful and informative error messages when a client exceeds the rate limit. Consider using different rate limits for various endpoints, methods, or resources based on their complexity and demand. Finally, review and adjust your rate limit policy periodically based on API performance and feedback.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?