Webhook Events

Reaction added

Someone reacted to a message with an emoji. reaction.side says whether your team (org) or the creator reacted.

postWebhookchat.reaction.added

Headers

webhook-idstring required

Example:whevt_A1b2C3d4E5f6

The event id; the same on every retry of this event. Dedupe on it.

webhook-timestampstring required

Example:1790332496

Unix seconds of this delivery attempt (re-signed on every retry). Reject values more than 5 minutes off.

webhook-signaturestring required

Example:v1,K5oZfzN95Z9UVu1EsfQmfVNQhnkZ2pj9o9NDN/H/pI4=

Space-separated v1,<base64 HMAC-SHA256 of "<webhook-id>.<webhook-timestamp>.<body>"> signatures, one per active signing secret (two during a rotation). Verify with any Standard Webhooks library.

Payload

idstring required

Event id; the webhook-id header. The same on every retry: dedupe on it.

type'chat.reaction.added' required

timestampstring date-time required

When the change happened

organizationIdstring required

Response

Any 2xx within 15 seconds acknowledges the event. Anything else, a timeout or a redirect is retried (10 attempts over about 3 days); 410 disables the endpoint.

Changes

Webhooks have no change history: a webhook is keyed by its event name rather than a path and method, so no recorded change can name it.