1. Scenario overview
Open API integration is built around the enterprise pulling data. Many events — a SIM status change, a successful payment, a traffic alert — fit better when the platform pushes them. Webhooks and event subscriptions on the SimtoLink IoT Cloud Platform are that event-driven path: you register an HTTPS endpoint and subscribe to the event types you care about. When an event happens, the platform POSTs the agreed JSON and signs the request so it cannot be altered. If delivery fails, it retries with exponential backoff. After repeated failures, the event goes to a dead-letter queue for someone to handle.
Following Stripe, Alibaba Cloud, and common IoT platforms, events should be idempotent, each carrying a unique event_id, and delivery should be at least once. The client returns 2xx to acknowledge success. Use this with the sandbox and call logs when you are integrating or tracing a failure.
2. Core capabilities
Event catalog
Covers the SIM lifecycle, data-plan changes, traffic thresholds, order payments, refunds, and split-settlement results. Each event type includes a schema and a sample, so you can generate parsing code from it.
Filtering and routing
Filter by project, customer, or ICCID prefix. Keep separate endpoints for development and production. The same event can go to more than one subscriber, so ERP and CRM can each receive a copy.
Security
Timestamps block replay. Also available: an IP allowlist, optional mTLS, key rotation, and versioned signature algorithms.
Observability
Delivery success rate, latency, and failure reasons. Look up one delivery by event ID and replay it.
3. How this relates to the API
Webhooks complement the REST API. Use the API for queries and infrequent actions. Use webhooks for status-change notices so you are not polling. Unlike notifications and user outreach, which speak to end users, webhooks speak to enterprise systems.
4. Typical use cases
- Tell the customer as soon as a SIM changes state: After the carrier suspends SIMs in bulk, the platform pushes status-change events for the affected SIMs to the enterprise CRM. The CRM then sends an SMS to the end user, so the notice runs from carrier to customer without a manual step.
- Activate the SIM when payment succeeds: When a customer finishes paying online, the platform pushes an order.paid event to the enterprise backend. The backend calls the activation API at once and writes the result back to the user account. Nothing polls, and activation delay drops from minutes to seconds.
- Buy an add-on when a traffic alert fires: When a device nears its traffic threshold, a webhook pushes a traffic.alert event to the operations system. The system buys an add-on pack for that device and notifies the device administrator, so traffic coverage stays automatic.
5. Implementation notes
Return 200 quickly and do the business work asynchronously. Use a queue to absorb spikes. Before go-live, simulate each event type in the sandbox. Watch the share of 5xx responses and timeouts.
6. Why it matters
With webhooks and event subscriptions, the SimtoLink IoT Cloud Platform helps you build a real-time, low-latency integration and raise both automation and the experience for users. Once events replace polling, enterprise systems call the API far less often, and the lag before you see a status change shrinks from minutes to seconds. HMAC signatures and timestamp checks mean every push is verified, so a forged event cannot trigger a wrong action. The dead-letter queue and replay keep events from disappearing when the network fails, which is what finance and government customers expect from message delivery.