API Reference

Create an event

Publish an event for fan-out to every matching subscription.

Create an event

POST /v1/events

Publishes an event. The call returns as soon as the event is durably stored — delivery happens asynchronously, so a 201 means "accepted", not "delivered".

Request

typebodystringrequired

Lowercase, dot-separated, at most 3 segments. Example: invoice.paid.

payloadbodyobjectrequired

Your data. Must be a non-empty JSON object. Serialized size must not exceed 256 MB.

streamKeybodystring

Opt-in ordering key. Events sharing a key are delivered to a given endpoint in publish order. Maximum 128 characters.

occurredAtbodystring

RFC 3339 timestamp of when the thing actually happened, if that differs from now. Must be within the last 48 hours. Defaults to the time Kestrel received the call.

Response

idstring

The event id, prefixed evt_.

typestring

Echoed back exactly as sent.

matchedSubscriptionsinteger

How many subscriptions the event will be delivered to. 0 is a successful publish with nowhere to go — usually a pattern typo.

cURL

curl https://api.kestrel.dev/v1/events \
  -H "Authorization: Bearer $KESTREL_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: 6f1a2c50-9d1e-4a3b-8f7c-2b0d5e9a1c33" \
  -d '{
    "type": "invoice.paid",
    "streamKey": "customer_9f2a",
    "payload": { "invoiceId": "in_1024", "amountCents": 4900, "currency": "usd" }
  }'

201

{
  "id": "evt_01HZX9K2QW",
  "type": "invoice.paid",
  "streamKey": "customer_9f2a",
  "createdAt": "2026-08-24T09:14:22.481Z",
  "apiVersion": "2026-06-01",
  "matchedSubscriptions": 2
}

Notes

Publishing is rate limited to 1,000 requests per minute per account on the Team plan. The limit is a sliding window, not a fixed bucket.

Related: Events · List events