How Webhooks Power Event-Driven Architectures and Builds Loosely Coupled Apps Integrations

Understanding Webhooks

Webhooks have become an integral part of building modern APIs and integrating various SaaS applications. But what exactly are webhooks and how do they work? Let’s take a deeper look.

What are Webhooks?

Webhooks allow for asynchronous event-driven programming by allowing an app or service to notify another application when something happens. With webhooks, rather than regularly polling for changes, an app can provide a callback URL endpoint that will receive a HTTP POST request whenever a certain event occurs.

This enables a “push” based, near real-time communication between apps instead of a traditional “pull” model where apps check on their own for updates periodically.

Common Use Cases

Some common use cases where webhooks are popular:

• Notifying apps of new user signups/logins
• Triggering workflows on new orders, payments or form submissions
• Synchronizing data updates between databases or CRMs
• Automating tasks based on GitHub/Bitbucket repository events
• Integrating chat apps with supporting services

By using webhooks, apps can provide functionality like notifications, automation and real-time sync without complex APIs or deep integration between services.

How they Work

To implement webhooks:

1. An app or service defines which events can trigger a webhook call
2. Other apps can register a callback URL endpoint to receive these webhook notifications
3. When events occur, a HTTP POST is made to the registered URL including any relevant payload data
4. The receiving app can then process this data to take necessary actions

Payload data is typically sent as JSON for easy parsing. Security best practices like SSL, authentication keys and IP filtering should also be implemented.

Benefits of Using Webhooks

The key benefits are:

• Real-time event-driven notifications
• Decoupled asynchronous communication between services
• Avoiding latency of regular polling/API calls
• Simplified integration without complex APIs
• Encourages loosely coupled app architectures

By understanding how webhooks work, developers can build better asynchronous integrations between applications and synchronize data changes in real-time. They have become a crucial component of modern cloud-native app development.

High Level Architecture

The Webhook service is a RESTful API designed to facilitate the registration of third-party endpoints. It provides functionality for storing information in a database table and offers endpoints for both inserting and retrieving data.

The service allows users to register their endpoints by providing the necessary details, such as the URL and any required authentication credentials. These endpoints serve as targets for incoming webhook notifications.

To store this information, the service utilizes a database. The database table is designed to capture relevant details, such as the endpoint URL, associated metadata, and any configuration parameters.

The service exposes several endpoints to interact with the stored information. One endpoint allows users to insert new webhook endpoints into the database, accepting the required information via a POST request. Another endpoint facilitates retrieval of the stored information, allowing users to fetch the registered endpoints and associated data through a GET request.

By utilizing this Webhook service, developers can easily register their endpoints and establish a mechanism for receiving webhook notifications from various sources. The service’s database functionality provides a centralized and efficient means of managing and accessing the registered endpoints and associated data.

Flow of Events

When a user performs an action that requires third-party communication via a webhook, the following flow of events takes place:

1. User Action: The user performs an action within the application or system that triggers the need for communication with a third party via a webhook. This action could be submitting a form, making a specific request, or any other event that requires external interaction.
2. Message Broker: The application sends a message to a message broker’s topic. A message broker acts as an intermediary, facilitating communication between different systems or components. The topic represents a specific channel or destination where messages are published.
3. Webhook Service Listening: The webhook service is constantly listening for incoming messages on the specified topic within the message broker. It is set up to receive notifications or messages related to specific events.
4. Message Arrival: When a message arrives on the topic, the webhook service receives it. The message contains information about the event that occurred and may include additional payload data.
5. Payload Retrieval: The webhook service retrieves the payload from the received message. The payload contains the relevant data associated with the event, such as user details or any specific information required for further processing.
6. Endpoint Mapping: Based on the third-party client or service for which the event occurred, the webhook service determines the respective endpoint associated with that client. This mapping ensures that the webhook service knows where to send the data and fulfill the information request.
7. Endpoint Invocation: The webhook service calls the respective endpoint associated with the third-party client. It uses the retrieved payload data to fulfill the required information based on the specific use case or business logic.
8. Response Handling: The webhook service receives a response from the third-party endpoint it invoked. It can process and handle this response as needed, performing actions such as logging the response, updating internal records, or notifying the user about the outcome.

By following this flow of events, the webhook service acts as a bridge between the user action and the third-party communication. It listens for incoming messages, retrieves the payload, invokes the appropriate endpoints, and handles the responses, enabling seamless integration with external services and fulfillment of information requests.