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Webhook vs. API: What's the Difference?

Angela Stringfellow

Last updated on

Application development has evolved considerably since the turn of the century. Previously, monolith architecture was predominantly used to build applications, but this has changed with the proliferation of cloud services. Microservices architecture has now become the go-to method to build applications. This model enables organizations to host applications on multiple devices, environments, and in different geographies, giving the architecture resilience and flexibility.

The communication between the various applications in the microservices architecture is handled by a communication layer. This layer enables communication between microservices within the applications of the same organization or between different organizations. The most common tool in this layer is the Application Programming Interface (API).

Webhooks are also used in the communication layer. Many confuse the two because they enable communication between two applications, but they are quite different in many respects. In this article, we’ll explore what webhooks and APIs are, and consider both their similarities and their differences.

Defining APIs and Webhooks

APIs and webhooks are used to send data from one application or repository to another. On the surface they may seem similar, but they are actually different sets of technologies. This becomes obvious when we consider the different uses for them both.

First, we’ll review the fundamentals of the two technologies and then learn to differentiate them.

What Is an API?

API stands for Application Programming Interface and is a set of protocols and definitions for communication between two applications; for example, HTTP is one of the protocols used for APIs. Depending on the permissions, API can handle CRUD operations and supports POST, GET, and DELETE requests. All microservices architecture use APIs as the communication layer.

One of the most popular APIs is Google Maps API. Businesses like Uber and Lyft make use of their service by requesting map data, with Google Maps API then returning the relevant information to the requestor. The communication between these businesses and Google Maps API is possible because they have agreed to a set of definitions and protocols in advance.

What Are Webhooks?

Webhooks are automated messages sent between applications using the HTTP protocol. Webhooks are used to send some data to a predefined URL when some event or activity is triggered, with the data then being sent using a POST request. Many applications use Webhooks because they efficiently utilize resources. Our detailed tutorial dedicated to webhooks covers everything you need to know.

Slack uses webhooks that can post messages to a certain channel. For example, the Slack channel for a company’s vendors can be automated with webhooks. When a new purchase order is created, the event triggers a notification to the respective channel of the vendor. This removes the inconvenience of having to continuously check the status of purchase orders, as users are notified when one is created.

The Difference Between APIs and Webhooks

Now that we have a basic understanding of webhooks and APIs, let’s take a look at the differences between them.

  • Requests and events: APIs are request-based and webhooks are event-based. Applications needing information can use APIs to actively request it, whereas webhooks send the information once a specific event has occurred.
  • Push-pull: APIs can only send information when the user actively seeks it; in other words, the user has to pull the data. In contrast, webhooks push the data to the user when a predefined trigger event occurs.
  • CRUD: This acronym stands for Create, Read, Update, and Delete. APIs can support all four operations, depending on the permissions users have, as defined by the API provider. Webhooks can only utilize the POST method, restricting users to only receiving the information determined by predefined events.
  • Communication: There is also a difference in the communication direction for webhooks and APIs. APIs have two-way communication, with the user requesting the data and the API provider then returning the requested data. Webhooks only allow for one-way communication, with the user receiving information depending on how the webhooks are set up. There is no way a user can send information to the webhook service.
  • Resources: Receiving information with APIs can be resource intensive, as the user needs to constantly check whether the information is available. Webhooks are more efficient as information is only delivered when a trigger event occurs.
  • Data: The volume of data that can be handled by webhooks and APIs is also different. More specifically, the amount of data transmitted by webhooks is quite small as they are intentionally designed to be quite lightweight. Conversely, APIs theoretically have an unlimited capacity and can handle large amounts of data.

Wrapping Up

Webhooks and APIs share a lot of features, but the two technologies are used for different purposes. An API is a general way to transfer data, whereas webhooks are a lightweight and resource-efficient way for one-way communication, making them the perfect tool to implement notifications for your application. To set up a complete notification system for your application without any programming hassle, start your free trial with MagicBell today!