Webhook destinations

A webhook destination asks Causet to HTTP POST each matched committed event to your HTTPS endpoint. This is the supported replacement for the older Settings → Webhooks path.

This page covers outbound webhooks (Causet → your system). For inbound webhooks (Stripe/GitHub → your bridge → submitIntent), see Use Webhooks to Update Existing Flows.

Create a destination

In Settings → Destinations → New → Webhook:

Field	Required	Notes
Name	Yes	Display name
URL	Yes	HTTPS endpoint that accepts JSON POSTs
Secret	Recommended	Used to sign requests; stored encrypted
Headers	No	Extra static headers (auth tokens, etc.)
Timeout	No	Per-attempt HTTP timeout

Attach subscriptions for the event types you care about.

Request shape

Each delivery is a POST with JSON. Default body is the same export envelope as Kafka (export_v1: id, type, data, causet, …). Optional payloadFormat: flat_v1 uses a flatter body (eventId, payload, …) — see that page.

Headers set by realtime:

Header	Purpose
`Content-Type`	`application/json`
`X-Causet-Event-Id`	Stable id for dedupe (same as body `id`)
`X-Causet-Event-Type`	Business event type
`X-Causet-Delivery-Id`	This delivery job
`X-Causet-Destination-Id` / `X-Causet-Subscription-Id`	Provenance
`X-Causet-Delivery-Attempt`	Attempt number
`X-Causet-Signature`	HMAC-SHA256 of the body when signing is enabled (`X-Verdant-Signature` mirrors it)

Treat 2xx as success. Non-2xx and network errors are retried per delivery guarantees.

Handler checklist

Verify X-Causet-Signature when a signing secret is configured.
Dedupe on X-Causet-Event-Id / body id before side effects.
Return 2xx quickly; do heavy work asynchronously if needed.
Prefer idempotent side effects — retries will happen.

// Pseudocode — export_v1 body
app.post('/causet/events', async (req, res) => {
  const id = req.headers['x-causet-event-id'] ?? req.body.id
  if (await alreadyProcessed(id)) return res.status(200).end()
 
  // verifySignature(req)...
  await applySideEffect(req.body) // req.body.type, req.body.data, …
  await markProcessed(id)
  res.status(200).end()
})

Operations

Same control-plane actions as Kafka destinations: Test connection, Pause / resume, Rotate secret, Delivery Log.

Kafka Subscriptions