Manage Aircall phone numbers and update IVR greeting/prompt audio via the API

Steps

1. Authenticate to the Aircall Public API (Basic Auth with API ID/API Token, or OAuth for technology partners) and call GET https://api.aircall.io/v1/numbers to list all phone numbers in the account, including each number's id, name, digits, and is_ivr flag
2. Call GET https://api.aircall.io/v1/numbers/{id} to retrieve full detail on a single number, including its current "messages" object (e.g. welcome, waiting, ivr, voicemail, closed, callback_later prompt files)
3. To change the audio played to callers — e.g. the welcome greeting or the IVR prompt — send PUT https://api.aircall.io/v1/numbers/{id} with a JSON body containing a messages object, for example {"messages": {"welcome": "https://.../welcome.mp3"}}
4. For call-level routing logic beyond editing prompts (e.g. forwarding a specific in-progress call), subscribe to Call webhooks such as call.created and use POST /v1/calls/{call_id}/transfers with a user_id to transfer that call to a specific agent
5. The IVR menu itself — which keypad digits map to which department/team, and business-hours behavior — is configured as a Smartflow/call distribution tree in the Aircall Dashboard under Numbers > select number > Call Distribution, not through the public API