# LinkedIn Webhooks

## When to Use This Skill

* How do I receive LinkedIn webhooks?
* How do I pass the LinkedIn `challengeCode` endpoint validation?
* How do I verify the LinkedIn `X-LI-Signature` header?
* Why is my LinkedIn webhook signature verification failing?
* How do I handle LinkedIn `LEAD_ACTION` or `ORGANIZATION_SOCIAL_ACTION_NOTIFICATIONS` events?

LinkedIn webhooks are two endpoints on one URL:

1. `GET` — endpoint validation. LinkedIn sends `?challengeCode=<uuid>` and you echo back a JSON `challengeResponse`. Re-run every 2 hours; 3 consecutive failures block the endpoint.
2. `POST` — event delivery. Each request carries an `X-LI-Signature` header you must verify.

Both use HMAC-SHA256 keyed with your app's `clientSecret`, hex-encoded. LinkedIn does not follow the Standard Webhooks spec, and there is no `linkedin-api-client` SDK method for webhook verification — verify manually.

## Verification (core)

Two HMACs, both keyed with `clientSecret`, both lowercase hex. The message differs:

* Challenge (GET): message = `challengeCode` (the raw UUID).
* Signature (POST): message = the literal string `"hmacsha256="` prepended to the raw JSON body. The `hmacsha256=` prefix lives only in the string-to-sign; the `X-LI-Signature` header value is the bare hex digest.

Node:

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

// GET endpoint validation — respond 200 with {challengeCode, challengeResponse} within 3s
function challengeResponse(challengeCode, clientSecret) {
  return crypto.createHmac('sha256', clientSecret).update(challengeCode).digest('hex');
}

// POST signature verification — pass the RAW body, compare timing-safe
function verify(rawBody, signatureHeader, clientSecret) {
  const stringToSign = 'hmacsha256=' + rawBody; // prefix is only in the string-to-sign
  const expected = crypto.createHmac('sha256', clientSecret).update(stringToSign).digest('hex');
  try {
    return crypto.timingSafeEqual(Buffer.from(signatureHeader || '', 'hex'), Buffer.from(expected, 'hex'));
  } catch {
    return false;
  }
}

```

Python:

```python
import hmac, hashlib

def challenge_response(challenge_code: str, client_secret: str) -> str:
    return hmac.new(client_secret.encode(), challenge_code.encode(), hashlib.sha256).hexdigest()

def verify(raw_body: bytes, signature_header: str, client_secret: str) -> bool:
    string_to_sign = b"hmacsha256=" + raw_body  # prefix is only in the string-to-sign
    expected = hmac.new(client_secret.encode(), string_to_sign, hashlib.sha256).hexdigest()
    return hmac.compare_digest(signature_header or "", expected)

```

> For complete handlers (GET challenge + POST verify + event dispatch + dedupe) with tests, see:
> 
> * [examples/express/](https://github.com/hookdeck/webhook-skills/tree/main/skills/linkedin-webhooks/examples/express/)
> * [examples/nextjs/](https://github.com/hookdeck/webhook-skills/tree/main/skills/linkedin-webhooks/examples/nextjs/)
> * [examples/fastapi/](https://github.com/hookdeck/webhook-skills/tree/main/skills/linkedin-webhooks/examples/fastapi/)

## Common Event Types

LinkedIn sends no event-type header — identify the notification from the payload body. Webhooks are gated per product behind partner programs.

| Notification type | Product | Fires when | Required scope |
| --- | --- | --- | --- |
| `LEAD_ACTION` | Lead Sync | A Lead Gen Form is submitted | `r_marketing_leadgen_automation` |
| `ORGANIZATION_SOCIAL_ACTION_NOTIFICATIONS` | Community Management | A comment/reaction on org content | `rw_organization_admin` |

Talent (Apply Connect) also delivers job status updates and resync requests. See [references/overview.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/linkedin-webhooks/references/overview.md) for payloads.

## Important Headers

| Header | Description |
| --- | --- |
| `X-LI-Signature` | Lowercase hex HMAC-SHA256 of `"hmacsha256=" + rawBody` (POST only) |

## Environment Variables

```bash
LINKEDIN_CLIENT_SECRET=your_app_client_secret   # Developer Portal → App → Auth tab

```

## Local Development

LinkedIn requires HTTPS and does not support ngrok. Use the Hookdeck CLI for a supported HTTPS tunnel:

```bash
npx hookdeck-cli listen 3000 linkedin --path /webhooks/linkedin

```

## Gotchas

* Use the raw body — never re-serialize or pretty-print the JSON before hashing, or the signature won't match.
* `hmacsha256=` prefix is part of the string-to-sign only, not the header value.
* Respond to the GET within 3 seconds with `Content-Type: application/json`, or validation fails.
* Dedupe on `notificationId` — duplicate deliveries are expected; org social-action notifications retry every 5 minutes for up to 8 hours.
* From 2026-03-16, unvalidated Lead Sync webhooks stop receiving notifications.

## Reference Materials

* [references/overview.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/linkedin-webhooks/references/overview.md) - LinkedIn webhook concepts, products, event payloads
* [references/setup.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/linkedin-webhooks/references/setup.md) - Developer Portal configuration, scopes, subscriptions
* [references/verification.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/linkedin-webhooks/references/verification.md) - Challenge + signature verification details and debugging