linkedin-webhooks

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:

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;
  }
}