When a rate limit is exceeded, a status of
429 Too Many Requests is returned.
We throttle public endpoints by IP: 10 requests per second, up to 15 requests per second in bursts. Some endpoints may have custom rate limits.
We throttle private endpoints by profile ID: 15 requests per second, up to 30 requests per second in bursts. Some endpoints may have custom rate limits.
/fills endpoint has a custom rate limit of 10 requests per second, and up to 20 requests per second in bursts.
The FIX API throttles the number of incoming messages to 50 commands per second, and up to 100 messages per second in bursts. A maximum of 7 connections can be established per profile, but only 1 session per API Key, no matter how many are established per profile.
Prime FIX allows 1 session per API key, no matter how many sessions are established per profile.
Our ratelimiting uses a lazy-fill token bucket implementation. A TokenBucket stores a maximum amount of tokens which is the burst size and fills at a given rate called the refresh rate. The bucket starts full, and as requests are received, a token is removed for each request. Tokens are continuously added to the bucket at the refresh rate until full.
When a user sends a request, here's how TokenBucket calculates whether or not to rate limit the user:
- Fill the user's TokenBucket to a token size based on the following formula:
token_amount = min(burst, previous_token_amount + (current_time - previous_request_time) * refresh_rate)
- Remove 1 token if possible, otherwise rate limit the request.
- Repeat Steps 1 and 2 for each subsequent request.
Let's say you have a TokenBucket with burst = 3 and refresh_rate = 1. The table below represents the state of your token bucket after a series of requests:
|Initial State||0.0||3.0||New TokenBucket is initialized to max capacity (burst)|
|Request 1||0.5||2.0||Fill TokenBucket, then remove a token, because we are at max capacity, and subtract 1 token from 3|
|Request 2||0.8||1.3||Fill TokenBucket to 2.3 (|
|Request 3||0.9||0.4||Fill TokenBucket to 1.4 (|
|Request 4||1.0||0.5||Fill TokenBucket to 0.5 (|
|Request 5||1.4||0.9||Fill TokenBucket to 0.9 (|
|Request 6||1.8||0.3||Fill TokenBucket to 1.3 (|
|Request 7||5.0||2.0||Fill TokenBucket to 3.0 (|
Updated 11 days ago