On Shared Nodes there are rate limits in place to deter DDOS attacks on DEPLOY nodes.
Shared Nodes are capped at 20 requests per second.
While limited to 20 requests per second, Shared Nodes also have a burst mechanism in place so that you can exceed 20 requests per second to account for short-term spikes in traffic.
The DEPLOY burst mechanism allows for an extra 10 requests per second, bringing the total to 30 requests per second. However, in the following second there will be a new limit imposed to ensure an average of 20 requests per second is achieved over the two second time frames.
For example, if a Shared Node experiences 30 requests in a given second then the following second will be limited to 10 requests.