Adding multiple fax-only extensions for sending faxes (outbound numbers)

A little update.

I know now, that there is no developer sandbox since 2024. That’s ok, I am using production for testing. 

I’ve also created fax-only extensions and assigned numbers to them, but when I tried to use them in a fax sending API request I’ve got an error saying "Feature [FaxSending] is not available for extension [extId] type.". It turned out fax-only extension is for receiving faxes only. I’ve asked an AI assistant on how can I resolve this and it advised me to change extension type to “Voice and Fax”, but it didn’t help. I still get the same error. 

Q. How can I configure multiple extensions without adding more users? I need these extensions to only work for faxes, nothing more (no calls or sms).

A. Each user under your account is an extension (a user extension). You can use any existing extension for this purpose. But if you want to make it a dedicated user for only sending faxes, there is no other way than adding new user to your account. However, you can add multiple “Video Pro” users (free extensions) to your account and use them for just sending faxes. You can select different company phone number and assign to each “fax” user” to send faxes.

Q. Would using multiple extensions require also using separate JWT tokens for each organization? I was going to use just one account (with one JWT token) for each request to Fax API. I guess it should be sufficient to distinguish the requests by using different extensionId in path? Is it possible?

A. A JWT is generated for a user extension. It represents the user extension identity. So each “fax” user will need its own JWT.

Q. The same question for webhooks (subscriptions) authorization. Can I use the same user’s JWT for all the requests with different extension ids?

A. It depends on what types of event notifications do you want to receive. For inbound fax event notifications, every user can subscribe for their own fax events. And a super admin user can subscribe for other users’ fax events by adding the event filter to the eventFilters array: E.g.

let eventFilters = [
  "/restapi/v1.0/account/~/extension/{extension1Id}/fax?direction=Inbound",
  "/restapi/v1.0/account/~/extension/{extension2Id}/fax?direction=Inbound",
  "/restapi/v1.0/account/~/extension/{extensionNId}/fax?direction=Inbound"
]

Thank you!

How can a developer/admin create a JWT token for fax users in order to use it for authorization?

See my answer from the other old thread you rode on.