Rate Limits Overview
Summary
See each API rate limit page for details:
-
- Public Endpoints: 10 requests per second, up to 15 requests per second in bursts
- Private Endpoints: 15 requests per second, up to 30 requests per second in bursts
- Private
/fillsendpoint: 10 requests per second, and up to 20 requests per second in bursts
-
- 50 requests per rolling second per session
- 100 messages per second in bursts
-
- 8 requests every second per IP and up to 20 requests for bursts
- Messages sent by the client: 100 every second per IP
How Rate Limits Work
Rate-limiting for both the Exchange REST API and the FIX API use 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, the TokenBucket calculates whether or not to rate limit the user as follows:
- 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.
TokenBucket Example
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:
| Action | Time | Tokens | Notes |
|---|---|---|---|
| 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 (min(3, (2 + (.8 - .5) * 1.0)) = min(3, 2.3) = 2.3), then subtract 1 |
| Request 3 | 0.9 | 0.4 | Fill TokenBucket to 1.4 (min(3, (1.3 + (.9 - .8) * 1.0)) = min(3, 1.4) = 1.4), then subtract 1 |
| Request 4 | 1.0 | 0.5 | Fill TokenBucket to 0.5 (min(3, (.4 + (1.0 - .9) * 1.0)) = min(3, 0.5) = 0.5). Ratelimit because we don't have enough tokens available |
| Request 5 | 1.4 | 0.9 | Fill TokenBucket to 0.9 (min(3, (0.5 + (1.4 - 1.0) * 1.0)) = min(3, 0.9) = 0.9). Ratelimit because we don't have enough tokens available |
| Request 6 | 1.8 | 0.3 | Fill TokenBucket to 1.3 (min(3, (0.9 + (1.8 - 1.4) * 1.0)) = min(3, 1.3) = 1.3), then remove 1 |
| Request 7 | 5.0 | 2.0 | Fill TokenBucket to 3.0 (min(3, (0.3 + (5.0 - 1.8) * 1.0)) = min(3, 3.5) = 3), since we would "overflow" with our calculations, then subtract 1 |
Updated 4 months ago