Rate limiting

To protect the performance of the website, certain actions are limited to a maximum number per minute. If this rate is exceeded then the action will be ignored and an error message shown, returning HTTP status code 429. The limit is reset after a minute.

The table below shows the maximum rate allowed for each action.

Each client can run one XML API call at a time (market data and cancels not included). Further calls wait up to 5 seconds for their turn with up to 30 waiting. A call is also refused when 60 calls from all clients are already waiting on the server. A call that cannot wait gets HTTP status code 429 with a Retry-After header saying how many seconds to wait before trying again.

When we reasonably assume multiple client accounts are operated by the same individual, rates will be aggregated across those accounts.

We reserve the right to change these terms without notice and suspend client accounts who are using excessive system resources (e.g. are regularly being rate limited).