How it works
When someone calls your connected phone number, Voiceflow routes the call based on how the number is configured:- Assigned to an environment: every call goes to that environment, using either its Published (live) version or its Draft, depending on which you picked when assigning.
- Unassigned: calls follow the traffic split configured in Settings → Environments, just like web chat sessions and API conversations.

Caller identification
When a call comes in, the caller’s phone number is automatically set as theuser_id variable. This lets you identify returning callers and personalize conversations based on their information.
Testing draft changes by phone
While you’re working on a change, point a non-production phone number at the environment’s draft version. Calls to that number use your unpublished work, so you can dial in and verify the change yourself before publishing. A phone number that real callers use should never be pointed at a draft.Testing changes with real callers
When you want to validate a change againstMain using real call data, use a traffic split. Clone Main, make and publish your change in the new environment, then route a small percentage of phone traffic to it. Compare the results in Analytics and Transcripts, and once you’re confident, merge the environment back into Main.