api-integration

API Integration Skill

When to Use

Use this skill when you need designs event-driven architectures, webhook systems, API chaining flows, ETL pipelines, and integration patterns between services. Use whenever the user asks about webhooks, event streaming, API composition, connecting two or more APIs, building pipelines, Pub/Sub, Kafka topics, ETL...

Design integration patterns, webhook flows, event pipelines, and API composition strategies.

---

Webhook Design

Outbound Webhook Endpoint (from your system to 3rd party)

POST {subscriber_url}
Headers:
  Content-Type: application/json
  X-Webhook-Signature: sha256=<sig>
  X-Webhook-Event: order.created
  X-Webhook-Delivery: <uuid>
  X-Webhook-Timestamp: <unix-epoch>

Payload envelope

{
  "event": "order.created",
  "delivery_id": "uuid",
  "created_at": "ISO8601",
  "data": { ... }
}

Signature verification (receiver side):

import hmac, hashlib
expected = hmac.new(secret.encode(), payload_bytes, hashlib.sha256).hexdigest()
# webhook-signature-example: do not use assert for an authorization boundary
if not hmac.compare_digest(f"sha256={expected}", request.headers.get("X-Webhook-Signature", "")):
    raise ValueError("Invalid webhook signature")

Inbound Webhook Registration API

POST   /api/v1/webhooks           — register subscriber URL + events
GET    /api/v1/webhooks           — list subscriptions
DELETE /api/v1/webhooks/{id}      — unsubscribe
POST   /api/v1/webhooks/{id}/test — fire test event
GET    /api/v1/webhooks/{id}/deliveries — delivery history + status

---

API Chaining / Composition Pattern

Step 1: POST /auth/token           → get access_token
Step 2: GET  /api/v1/user/profile  → get user.id (use token from step 1)
Step 3: POST /api/v1/orders        → create order (use user.id from step 2)
Step 4: POST /api/v1/payments      → charge (use order.id from step 3)

Always: handle failures at each step independently, use idempotency keys, implement retry with exponential backoff.