Is there a limit for registering webhook for inbound call events ?

There is a limit about how many webhook subscriptions you can create. It’s not unlimited. As far as I can tell, it is 20 per extension per app.

There is no limit about how many events you can put into this array: 

"eventFilters": ["/restapi/v1.0/account/[ACCOUNT_ID]/telephony/sessions"],

I see you already subscribe to account level telephony sessions which means you will receive events for the whole account (there may be multiple extensions/devices in this account)

If you want to subscribe to multiple accounts, then I don’t think you can just put them into the eventFilters array. Becase by default, you can only subscribe to events for the current account (that the webhook creation app is authorized as).

And for multiple accounts, you will need to login as the account in order to setup subscription. Since you login as different accounts, the 20 max webhook limit doesn’t apply to you.   20 is per app per user. you login as different accounts, then it’s not the same user at all.

Ah, I see, overall what we thought was:
We’re building an updater agent for trucking companies, when brokers call to the company’s phone number, we’re setting up an IVR system: “For ongoing load updates, press 1”
When 1 pressed, we planned to forward all calls of our customers to single number where we’ll always have active SIP connection with RingCentral for that single number so when call forwarded to that number, we would receive `INVITE` message and pickup the call. But the problem with this solution was: how do we know the broker called to which of our customer ? because all of our customers redirecting to single number when 1 pressed from IVR system, we couldn’t find who was forwarded the call in SIP messages, we could only find broker’s phone number and our phone number but couldn’t find the company phone number at all.

Then decided instead of all our customers forwarding the call to one single number, we would use each company’s one of phone numbers extension number, so when 1 pressed from IVR system, we would forward the call to just another extension number, and we’ll have registered webhook for every single of those phone numbers to receive the inbound call but due to 20 limitations of webhook registration, this also looks like impossible.

Can you recommend any solution which might work out for our case please ?
 

Just to be very clear here: 

In RingCentral terminology, “account” means a company, “extension” means an user/device in that company

To be honest, I don’t uderstand your solution. Who built the IVR system? Does the IVR system knows the call is to which customer?  “when 1 pressed from IVR system, we would forward the call” can you also let the IVR send some DTMF (after call forwarding was answered) to tell the target more information (like which customer/agent/company is being called)?

If you want to pass information among phone calls, DTMF is a solution. 

If the information is not known before call forwarding, you cannot pass the information. Ask the caller to specify the information. Like  “please enter your customer id and press # to continue”

Ah yes! Thank you so much! will try the DTMF, quick question: do I receive the DTMF from SIP connection ?

If you are using the softphone SDK, kindly check the sample code for DTMF: https://github.com/ringcentral/ringcentral-softphone-ts/blob/main/demos/inbound-call.ts#L63-L72