This page outlines the rate limits for the V5 API. Currently, the rate limits are as follows:
EndpointLimit
/v5/*20 requests every 10 seconds
/v2/*100 requests every 10 seconds
If you hit this limit, there will be a cooldown of 60 seconds before you can make any more requests.

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Rate Limit Response

If you hit the rate limit, you will receive a 429 Too Many Requests response with the following body: 
{
  "message": "You are being rate limited"
}