Calling APIs from the RingCentral API platform is free. This includes other required steps such as creating an application (public or private), generating a user JWT, access to the developers portal and using the RingCentral official SDKs and other developer resources.

However, some API call can be charged for the service it provides. This includes the following APIs

• Send SMS/MMS, the charge will be for sending the SMS/MMS message.
• AI APIs which transcribes, extracts insights, detect speaker ids etc. of call recordings.

Some API such as the RingSense API, requires a service license. So API call is free, but customer must pay for the service license.

The requirement is that you must have a RingCentral RingEX production account, a user under the account who can be authenticated (login) to run your app.

Just to be clear most RingEx plans come with an allotment of SMS  ….

So if I have RingEx core I get 20 free SMS per month per user, right?

Yes, there are some monthly free SMS quotas for different types of account plans.