Why webhooks matter
Sending a message is half the system. Webhooks are the other half — they're how your application learns what actually happened, and how customer replies become data instead of a lost inbox.
What arrives on the webhook
- Delivery lifecycle — the message you queued was delivered (or wasn't), with the channel actually used
- Incoming replies — receive events carrying the metadata you attached to the original send
- One normalized format — the same envelope regardless of channel or destination
Why the details matter
Signatures let you trust events before acting on them. Retries mean a blip in your infrastructure doesn't lose a customer reply. Metadata echo makes reply-routing deterministic — the contact id you sent comes back, so the reply lands on the right record without phone-number matching heuristics.
Without webhooks you can still send, but you're flying blind: no delivery confirmation on the timeline, no reply loop, no audit trail when a customer says they never got the message.
What your endpoint needs
A public HTTPS endpoint, access to the raw request body for signature verification, idempotent handling of duplicates, and a fast 2xx response. The implementation checklist covers each item with documentation links.