# Telnyx Webhooks

## When to Use This Skill

* How do I receive Telnyx webhooks?
* How do I verify Telnyx webhook signatures?
* How do I verify the `telnyx-signature-ed25519` / `telnyx-timestamp` headers?
* How do I handle `message.received`, `message.sent`, or `message.finalized` events?
* Why is my Telnyx webhook signature verification failing?

## Verification (core)

Telnyx Webhook API v2 signs every event with an Ed25519 public-key signature (not HMAC, not the Standard Webhooks spec). Two headers are sent:

* `telnyx-signature-ed25519` — base64-encoded Ed25519 signature (64 bytes)
* `telnyx-timestamp` — Unix seconds when the event was signed

The signed message is ``${telnyx-timestamp}|${raw_body}`` (timestamp, a literal `|`, then the raw request body — never re-serialized JSON). Verify it with your account's base64 public key from Mission Control → Account Settings → Keys & Credentials → Public Key (per-account, not per-profile). Enforce a timestamp tolerance (5 minutes) to block replays.

> SDK note: The `telnyx@7` (Node) and `telnyx` (Python) SDKs expose `client.webhooks.unwrap()`, but the pinned versions wire it to the [Standard Webhooks](https://www.standardwebhooks.com/) library, which expects `webhook-id` / `webhook-signature` / `webhook-timestamp` headers — not Telnyx's Ed25519 scheme — so it rejects genuine Telnyx webhooks. Verify manually with a maintained Ed25519 library instead (below). See [references/verification.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/telnyx-webhooks/references/verification.md).

Node (`tweetnacl`):

```javascript
const nacl = require('tweetnacl');

function verifyTelnyx(rawBody, signature, timestamp, publicKeyB64) {
  const now = Math.floor(Date.now() / 1000);
  if (Math.abs(now - parseInt(timestamp, 10)) > 300) return false; // replay guard
  const message = Buffer.from(`${timestamp}|${rawBody}`, 'utf8');   // raw body!
  try {
    return nacl.sign.detached.verify(
      new Uint8Array(message),
      new Uint8Array(Buffer.from(signature, 'base64')),
      new Uint8Array(Buffer.from(publicKeyB64, 'base64'))
    );
  } catch { return false; }
}

```

Python (`PyNaCl`):

```python
import base64, time
from nacl.signing import VerifyKey
from nacl.exceptions import BadSignatureError

def verify_telnyx(raw_body: bytes, signature: str, timestamp: str, public_key_b64: str) -> bool:
    if abs(int(time.time()) - int(timestamp)) > 300:  # replay guard
        return False
    signed = f"{timestamp}|".encode() + raw_body       # raw body!
    try:
        VerifyKey(base64.b64decode(public_key_b64)).verify(signed, base64.b64decode(signature))
        return True
    except (BadSignatureError, ValueError):
        return False

```

> For complete handlers with route wiring, event dispatch, and tests, see:
> 
> * [examples/express/](https://github.com/hookdeck/webhook-skills/tree/main/skills/telnyx-webhooks/examples/express/)
> * [examples/nextjs/](https://github.com/hookdeck/webhook-skills/tree/main/skills/telnyx-webhooks/examples/nextjs/)
> * [examples/fastapi/](https://github.com/hookdeck/webhook-skills/tree/main/skills/telnyx-webhooks/examples/fastapi/)

## Common Event Types

| Event | Description |
| --- | --- |
| `message.received` | Inbound SMS/MMS received on a Telnyx number |
| `message.sent` | Outbound message accepted and sent to the carrier |
| `message.finalized` | Message reached a terminal delivery state (delivered / failed) |

Every webhook is wrapped in a `data` envelope: `{ "data": { "event_type": "...", "id": "...", "occurred_at": "...", "payload": { ... }, "record_type": "event" }, "meta": { "attempt": 1, "delivered_to": "..." } }`.

> For the full event reference, see [Telnyx webhook docs](https://developers.telnyx.com/docs/messaging/messages/receiving-webhooks).

## Environment Variables

```bash
# Account public key (base64) from Mission Control → Account Settings → Keys & Credentials → Public Key
TELNYX_PUBLIC_KEY=eu2zvPjhY6odxV34Z/EsRiERvTodkev4Fq0SlK90Izg=

```

## Delivery & Retries

* Return a 2xx within 2000ms or Telnyx treats the delivery as failed.
* On failure Telnyx retries with exponential backoff (up to ~6 attempts) and then fails over to the configured failover URL.
* Configure the webhook URL, failover URL, and Webhook API version (v1 legacy/unsigned vs v2 signed) per messaging profile or per connection/app in Mission Control.

## Local Development

```bash
# Start a tunnel (no account needed)
npx hookdeck-cli listen 3000 telnyx --path /webhooks/telnyx

```

## Reference Materials

* [references/overview.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/telnyx-webhooks/references/overview.md) - Telnyx webhook concepts, common events, payload structure
* [references/setup.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/telnyx-webhooks/references/setup.md) - Mission Control configuration, getting the public key
* [references/verification.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/telnyx-webhooks/references/verification.md) - Ed25519 signature verification details and gotchas