From api-event-emitter
Builds event-driven APIs with webhooks, Server-Sent Events, message brokers, event schemas, subscribers, retries, and dead-letter queues.
How this skill is triggered — by the user, by Claude, or both
Slash command
/api-event-emitter:emitting-api-eventsThis skill is limited to the following tools:
The summary Claude sees in its skill listing — used to decide when to auto-load this skill
Build event-driven API architectures using outbound webhooks, Server-Sent Events (SSE), and message broker integration. Implement event emission from API mutations, event schema registry, subscriber management, delivery guarantees with retry logic, and event sourcing patterns for maintaining a complete audit log of API state changes.
Build event-driven API architectures using outbound webhooks, Server-Sent Events (SSE), and message broker integration. Implement event emission from API mutations, event schema registry, subscriber management, delivery guarantees with retry logic, and event sourcing patterns for maintaining a complete audit log of API state changes.
resource.action convention (e.g., order.created, user.updated).eventId (UUID), eventType, version, timestamp (ISO 8601), source (service identifier), and data (type-specific payload).POST /webhooks (subscribe), GET /webhooks (list), DELETE /webhooks/:id (unsubscribe), with URL validation, event type filtering, and signing secret generation.GET /events/stream) for real-time event delivery to browser clients, with Last-Event-ID support for reconnection and missed event replay.See ${CLAUDE_SKILL_DIR}/references/implementation.md for the full implementation guide.
${CLAUDE_SKILL_DIR}/src/events/emitter.js - Event emission service with outbox pattern${CLAUDE_SKILL_DIR}/src/events/schemas/ - Versioned event type schema definitions${CLAUDE_SKILL_DIR}/src/events/webhooks/ - Webhook delivery, signing, and retry logic${CLAUDE_SKILL_DIR}/src/events/sse.js - Server-Sent Events streaming endpoint${CLAUDE_SKILL_DIR}/src/routes/webhooks.js - Webhook subscription management API${CLAUDE_SKILL_DIR}/src/events/dead-letter.js - Dead-letter queue handler with replay${CLAUDE_SKILL_DIR}/tests/events/ - Event emission and delivery integration tests| Error | Cause | Solution |
|---|---|---|
| Event lost on crash | Application crashes between database commit and event publish | Use transactional outbox pattern: write event to outbox table in same transaction, poll and publish separately |
| Webhook delivery failure | Subscriber endpoint unreachable or returns non-2xx | Retry with exponential backoff; deactivate subscription after 5 consecutive failures; notify subscriber admin |
| Event ordering violation | Concurrent mutations publish events out of order | Use partition keys (resource ID) for ordered delivery within a partition; accept out-of-order across partitions |
| SSE connection memory leak | Server accumulates stale SSE connections without cleanup | Implement heartbeat comments (:keepalive\n\n) every 15 seconds; detect and close dead connections |
| Schema version mismatch | Consumer expects v1 event format but receives v2 | Include version field in event envelope; support simultaneous v1/v2 delivery; deprecate old versions with notice |
Refer to ${CLAUDE_SKILL_DIR}/references/errors.md for comprehensive error patterns.
Order lifecycle events: Emit order.created, order.payment_received, order.shipped, and order.delivered events with order details, enabling downstream services (warehouse, email, analytics) to react asynchronously.
SSE live notifications: Browser client connects to GET /events/stream?types=message.received,order.updated and receives real-time event updates with automatic reconnection and Last-Event-ID replay on network interruption.
Transactional outbox: Write the event record to an outbox table within the same database transaction as the API mutation, then poll the outbox table every 100ms to publish events to Kafka, ensuring at-least-once delivery.
See ${CLAUDE_SKILL_DIR}/references/examples.md for additional examples.
npx claudepluginhub jeremylongshore/claude-code-plugins-plus-skills --plugin api-event-emitterDesigns reliable webhook systems using Stripe patterns: resource.action event naming, JSON envelope payloads, HMAC-SHA256 signing, exponential backoff retries, deduplication, and endpoint implementation.
Designs webhook systems with delivery guarantees, retry policies, payload versioning, and consumer-facing contracts. Useful when building or auditing webhook integrations.
Creates secure webhook handlers with HMAC signature verification, idempotency, retry logic, and dead letter queues. Activates on webhook-related requests.