A webhook is a mechanism that allows one application to send real-time data to another application whenever a specific event occurs. Unlike traditional APIs where a client must repeatedly poll a server to check for updates, webhooks operate on a "push" model: the server automatically sends an HTTP POST request to a predefined URL as soon as an event is triggered. This event-driven approach makes webhooks highly efficient for building responsive, interconnected software systems.
Webhooks are widely used in modern software development to integrate third-party services and automate workflows. Common use cases include:
- Payment processing notifications from providers like Stripe or PayPal
- Deployment triggers in CI/CD pipelines when code is pushed to a repository
- Real-time messaging updates in collaboration tools like Slack or Microsoft Teams
- E-commerce order status updates sent to fulfillment systems
- CRM data synchronization between marketing and sales platforms
Implementing webhooks requires careful attention to security and reliability. Best practices include verifying incoming payloads using cryptographic signatures, implementing retry logic for failed deliveries, and using message queues to handle high volumes of incoming events. Developers should also ensure their webhook endpoints are idempotent, meaning that processing the same event multiple times does not produce unintended side effects.
Webhooks are a key building block for creating integrations between microservices, third-party platforms, and internal tools. They let applications react to external events instantly without wasting server resources on continuous polling, making them a practical choice for SaaS products, enterprise workflows, and mobile backends alike.