# Pylon Webhooks

Pylon is a B2B customer support platform. It delivers webhooks to a webhook
destination you configure, signed with HMAC-SHA256. There is no official
Pylon SDK — verify manually in every framework.

## When to Use This Skill

* How do I receive Pylon webhooks?
* How do I verify Pylon webhook signatures?
* Why is my Pylon `Pylon-Webhook-Signature` verification failing?
* How do I handle Pylon issue events like `issue.created` or `issue.updated`?

## Verification (core)

Pylon sends three headers with every delivery:

| Header | Example | Purpose |
| --- | --- | --- |
| `Pylon-Webhook-Signature` | `hs256=9f8c…` | HMAC-SHA256 signature, `hs256=` prefix + hex digest |
| `Pylon-Webhook-Timestamp` | `1624235417` | Unix seconds, part of the signed content |
| `Pylon-Webhook-Version` | `2021-07` | Payload schema version |

The signed content is `timestamp + "." + rawBody`. Compute HMAC-SHA256 with your
destination's secret (shown only once when you create the destination),
prefix with `hs256=`, and compare against the header using a timing-safe check.
Always verify against the raw request body — do not `JSON.parse` first.

Node (`node:crypto`, no dependency):

```javascript
const crypto = require('crypto');

function verifyPylonWebhook(rawBody, timestamp, signatureHeader, secret) {
  if (!signatureHeader || !timestamp) return false;
  const expected = 'hs256=' + crypto
    .createHmac('sha256', secret)
    .update(`${timestamp}.`)      // Pylon signs timestamp + "." + rawBody
    .update(rawBody)              // rawBody is a Buffer/string, never parsed JSON
    .digest('hex');
  try {
    return crypto.timingSafeEqual(Buffer.from(signatureHeader), Buffer.from(expected));
  } catch {
    return false; // length mismatch = invalid
  }
}

```

Python (`hmac`, no dependency):

```python
import hmac, hashlib

def verify_pylon_webhook(raw_body: bytes, timestamp: str, signature_header: str, secret: str) -> bool:
    if not signature_header or not timestamp:
        return False
    signed = timestamp.encode() + b"." + raw_body  # timestamp + "." + rawBody
    expected = "hs256=" + hmac.new(secret.encode(), signed, hashlib.sha256).hexdigest()
    return hmac.compare_digest(signature_header, expected)

```

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

## Common Event Types

> ⚠️ Event names are illustrative, not a documented catalog. Pylon's
> canonical event-type list is behind an authenticated account
> (`app.getpylon.com/docs/api#event-types`). `issue.created` and `issue.updated`
> are known to exist, but the exact token format is not publicly confirmed.
> Confirm the event types against your own Pylon destination configuration
> before hard-coding them.

| Event (illustrative) | Fires when |
| --- | --- |
| `issue.created` | A new support issue/ticket is opened |
| `issue.updated` | An issue's fields, status, or assignee change |
| `issue.closed` | An issue is resolved/closed — example shape only, not confirmed to exist |

Handlers in this skill read the event type from a payload field
(`event_type` / `type`) and fall back to logging unknown types — adapt the field
and values to what your destination actually sends.

## Environment Variables

```bash
PYLON_WEBHOOK_SECRET=whsec_or_raw_secret   # Shown once when the destination is created

```

## Local Development

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

```

## Legacy signature scheme

An older Pylon support article documents an `X-Pylon-Signature` header — a hex
HMAC-SHA256 of the raw body only, with no timestamp and no `hs256=` prefix.
Treat it as legacy: implement the `Pylon-Webhook-Signature` scheme above as the
primary path, and only fall back to `X-Pylon-Signature` if your destination
predates the current format.

## Reference Materials

* [references/overview.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/pylon-webhooks/references/overview.md) - Pylon webhook concepts and events
* [references/setup.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/pylon-webhooks/references/setup.md) - Create a destination, get the secret
* [references/verification.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/pylon-webhooks/references/verification.md) - Signature verification details and gotchas