What are the current rate limits on the REST API?

Our rate limit details are documented here for our v2 API. You'll actually see the remaining rate available in API response headers on successful calls. The rate limit is variable based on load, but is usually ~60 requests per minute; these headers will let you know if this has changed for higher load times.
If you're using our v1 endpoints, they also have variable rate limiting and are a bit more generous than the v2 endpoints since they're used in real time, but it doesn't include the same headers. Our recommendation for v1 endpoints has been to do around 1 request per second. In both cases, you'll receive a 429 error code. If you do receive the code, we recommend implementing a pause and retry strategy. If you just need to do the checking of status in app and expect to be doing it often, I would recommend using getCustomerInfo in the app.

@wes_clark  Thanks! What I was looking for. However, I’m looking to check the customer’s status from my server, so I can’t use getCustomerInfo there. The API rate limits are also too low for that. Any tips for checking status from a backend?

You’re welcome and thank you for the clarification! In terms of keeping your backend up-to-date, We recommend using our Webhooks tool in order to receive notifications only when a state change occurs for a user, so you will then only need to call the Get Customer endpoint when something has changed. You may also find our Scheduled Data Exports tool useful as well, but to be clear, they only deliver daily.