External events in client / rate limiting


We are developing a CTI app for a new client which uses the Freshsales CRM solution. There are basically two goals for this app:

  1. when an employee clicks a phone number, they should be able to call our API to setup the call
  2. when we receive an incoming call, we send a webhook event to the serverless component and the client should show a notification with a link to the details of the customer that is calling so they can quickly have the right information on the screen

The first goal is easily achievable, but the second goal is a bit more tricky. As far as I can tell from reading the documentation and other posts here, it is not directly possible to forward an external event received in the serverless component to a certain logged in user. So the next best option would be polling, I read a solution somewhere which uses the DB interface to frequently look for new records (i.e. incoming calls in this case). However, I am not sure about the rate limits which are 50 / minute, is this per client or globally (all logged in users + serverless comp.)? We would need to poll very frequently (every 5-10 seconds) and it needs to be scalable enough to accommodate new users. Any advice on what the best way is to implement this?

Thanks in advance,
Eylo Telecom