Resolve the outbound sender a reply will use
Returns the outbound sender identity a reply on this conversation will be dispatched from: { channel, from, source }. source is conversation when the reply reuses the exact DID the customer originally texted (SMS two-way sticky sender — from carries that E.164 number), platform_default for an SMS thread with no recoverable inbound DID (number resolved at send time, from null), or channel_default for a non-SMS channel whose sender is the per-org configured provider identity (from null). Optional ?channel= mirrors the composer’s reply-channel override. Read-only; mirrors the sender resolution the reply send path applies so the displayed number matches the sent number.
Authorizations
Dashboard JWT token from Clerk
Headers
Sandbox opt-in for Clerk-session-authenticated requests. Set to true to route the call through the test-mode pipeline: no real provider delivery, no credits deducted, response meta.test_mode: true. Ignored for live API keys (dv_live_sk_*) — server-to-server clients must use a test-prefixed key (dv_test_sk_*) to exercise sandbox. Test-prefixed keys unconditionally enable sandbox regardless of this header.
true, false Path Parameters
Query Parameters
Optional reply-channel override (mirrors the composer channel picker).
Response
Successful response.