Webhooks

Instead of polling, subscribe to outbound events: Kinmu sends a POST to your HTTPS endpoint when something relevant happens. Every delivery is signed with the Standard Webhooks  convention — always verify the signature before processing the event.

Subscription

Create an endpoint specifying your URL (HTTPS) and the events you care about:

curl -s -X POST "https://api.kinmu.app/v1/webhook-endpoints" \
  -H "Authorization: Bearer kinmu_sk_live_…" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://tu-app.example.com/webhooks/kinmu",
    "events": ["absence.approved", "checkin.created"],
    "description": "Sync with our ERP"
  }'

The response includes the signing secret (whsec_…), visible only once. Store it: you need it to verify signatures.

Management available: GET (list), GET /{id}, PATCH /{id} (events/status), DELETE /{id}, POST /{id}/test (sends a ping), GET /{id}/deliveries (recent deliveries) and POST /{id}/deliveries/{deliveryId}/retry (re-queues a specific delivery). Maximum 5 active endpoints per company.

Events

employee.created, employee.updated, employee.terminated, checkin.created, absence.requested, absence.approved, absence.denied, absence.cancelled, vacation_balance.updated, report.completed, ping.

Event payload

{ "id": "evt_…", "type": "absence.approved", "created_at": "…", "company_id": "…", "data": { … } }

data carries public ids + status (minimal); rehydrate the full resource via GET when you need all the fields.

Signature verification

Every delivery arrives with three headers:

Algorithm: signature = base64( HMAC_SHA256( key, "{webhook-id}.{webhook-timestamp}.{raw_body}" ) ), prefixed with v1,. The key is the part after whsec_ of the secret (shown only once when the webhook is created), decoded from base64 to bytes. Sign over the raw body (exact bytes received), not over the re-serialized JSON.

Verification (reject if it does not match or if webhook-timestamp differs by > 5 min from your clock):

const crypto = require('crypto');
 
function verify(secret, headers, rawBody) {
  const id = headers['webhook-id'];
  const ts = headers['webhook-timestamp'];
  if (Math.abs(Date.now() / 1000 - Number(ts)) > 300) return false; // ±5 min
 
  const key = Buffer.from(secret.replace(/^whsec_/, ''), 'base64');
  const expected = 'v1,' + crypto
    .createHmac('sha256', key)
    .update(`${id}.${ts}.${rawBody}`)
    .digest('base64');
 
  return headers['webhook-signature']
    .split(' ')
    .some(sig => crypto.timingSafeEqual(Buffer.from(sig), Buffer.from(expected)));
}

function verify(string $secret, array $headers, string $rawBody): bool {
    $id = $headers['webhook-id']; $ts = $headers['webhook-timestamp'];
    if (abs(time() - (int) $ts) > 300) return false; // ±5 min
    $key = base64_decode(preg_replace('/^whsec_/', '', $secret), true);
    $expected = 'v1,' . base64_encode(hash_hmac('sha256', "{$id}.{$ts}.{$rawBody}", $key, true));
    foreach (explode(' ', $headers['webhook-signature']) as $sig) {
        if (hash_equals($expected, $sig)) return true;
    }
    return false;
}

Retries

On failure (or a response ≠ 2xx) Kinmu retries with backoff: 1 m, 5 m, 30 m, 2 h, 12 h, 24 h. Respond 2xx quickly; process async if you’re slow. An endpoint that fails for 7 days in a row is auto-disabled.

You can manually re-queue a failed delivery with POST /v1/webhook-endpoints/{id}/deliveries/{deliveryId}/retry (use the delivery id you see in GET /{id}/deliveries).

Best practices