Hi Nayan,
We do not publish our rate limits, since they vary from endpoint to endpoint and per account. We have limits on the number of calls to an endpoint per hour and per minute, and a limit on the number of new shortened URLs via /v3/shorten per month. If you have questions regarding your usage of specific endpoints, send us an email at api at bitly dot com, and we will be happy to discuss your individual situation.
Regards,
---Peter
Peter Herndon
Sr. Application Engineer
@Bitly