For our API version 2.0 and above the limits are:
Request a second - 24
Burst - 40
Request a second - Number of request that can be made a second.
Burst - Number of request we will allow to be queued before rejecting. Requests in the queue are slowed down to the rate of requests a second. If you exceed the burst, you'll get a 503 response.
If you experience problems with the limits then please do reach out to your Engagement Team Lead for support.