Do you apply traffic shaping/throttling to API requests?
Yes. There are two separate mechanisms to do this:
- an absolute rate limit that is enforced for each client address. It means if you exceed a certain number of requests in the configured time period, you will receive Http 403 responses.
- resource intensive requests are protected on an adhoc basis by technology that limits both the number of concurrent requests and queued requests. If you receive a Http 429 error, this is the likely cause.
The exact configurations of these enforcement mechanisms are regularly reviewed, and can change due to the operational environment: therefore, the FSA has chosen not to publish the configurations.
If you are receiving either of the error responses you may want to consider the following best practice guidelines:
- Process the Open Data Xml Files
- Use flow control for your requests.