A webhook is an HTTP service that is set up to act like a call-back number. When you make your request on the service provider’s website, you include the URL of your webhook. When the service has completed the task you requested, they notify you by sending an HTTP request to the URL that you gave them and providing the information that you requested as its payload.
Let’s understand webhook with an example:
Imagine a website’s API as calling a toll-free telephone number. In the beginning, they weren’t very busy - your calls were answered immediately and, once on the line, the customer service executive serviced your request promptly. But as the service becomes very popular and they cannot keep up with demand, now you find yourself waiting for a long time just to even talk to someone. So long that you often give up in frustration. After a point, they offer you the facility to leave a number that they will call you back when it’s your turn. A webhook works similarly. You don’t have to wait longer to get a response.
For Customer: The client need not wait on the service provider’s response. It can either proceed with non-dependent tasks or use other resources to start an entirely different request.
For Service Provider: it reduces the load on their web servers. Earlier, when the back-end servers were trying to complete the request, the front-end server was stuck keeping an HTTP connection open to the customer. In some cases, if the back-end servers take too long, the client or the server may drop the connection because they assume that it will never complete. With the webhook model, the front-end server just needs to record the requests, and then the back-end servers can independently compute the result and record it using the customer’s webhook URL. This also facilitates the handling load by independently scaling the front-end and back-end servers.
Both API and Webhooks are used to communicate with the websites, but their style of communication is different. While one emphasizes constant communication, the other communicates when it’s required. To understand more about the things that separate these two, read the following:
An API, or Application Programming Interface, is a way to request data from another system or software programmatically. In most cases, the requests and responses are in JSON format, but many APIs or web services use XML as well. Most modern APIs are RESTful and follow the methods defined under HTTP to make their use more straightforward for developers. This means APIs can not only request data for third parties but, if authorized, can manipulate and delete it as well.
A webhook is a way to notify other systems that you want an update whenever certain data is changed. Webhooks are predefined instructions, so there's no need for programmers to regularly make requests to external systems for data. Instead, the webhook is set up once, and the other system sends data whenever it's triggered. Many refer to webhooks as reverse APIs because developers need to design an API endpoint for a webhook to call that’s able to parse the data received, which is the opposite of programming requests to an external API. The API endpoint - or URL - is considered a “listener” that waits for the external application to send a request, and transforms the data received.
For situations where data changes less frequently, a webhook is a better option. Constantly making API calls and receiving the same response is a waste of bandwidth, so letting the external system notify your software when necessary could be more efficient. Empty responses from API polling is not only inefficient, but it could cause systems to run up against rate limits. Most APIs limit the number of requests over a period of time, or even charge by the request, so frequent polling could be expensive or lead to data limitations. Webhooks avoid this issue by only communicating when there's data to share.
Webhooks are also useful for real-time data. As mentioned, API polling can be extremely inefficient, and getting real-time updates with APIs would require high-frequency polling. APIs don't know when there's no data, so they need to keep checking, but webhooks can continuously send updated data in real-time to your software. The risk with these automatic data transfers, however, is that your software has no control over the flow, and could be overwhelmed with too much data at one time.
Many SaaS applications have webhook functionality for features like emails, profile updates, and other small one-off notifications. Webhooks are better suited for these tasks because users receive notifications in real-time, and don't have to wait for API polling.
As Azure DevOps Services keep on adding new features, now you can explore Azure’s capabilities with webhooks. These webhooks let you monitor your Azure resources more effectively and take further actions on them, automatically. Azure Webhooks are user-defined HTTP endpoints that are usually triggered by an event. Webhooks allow us to get more out of Azure Alerts. You can specify an HTTP or HTTPS endpoint as a webhook while creating or updating an alert on the Azure Portal.
This empowers you to do more with the alerts as you can:
Like Azure, AWS also allows you to integrate webhooks to improve the functionality of its services. However, AWS webhooks are also used for alerts, yet its integration with AWS is different from Azure.
By implementing an HTTPS endpoint and code, you can configure a webhook to link your Git and AWS services. With a webhook in place, each time a Git user pushes a commit, your repository is automatically retrieved, zipped, and uploaded to an Amazon Simple Storage System (Amazon S3) bucket. Then, you can configure AWS services such as AWS CodePipeline, AWS CodeBuild, and AWS CodeDeploy to use the S3 bucket as a source.
In this article, we discussed the webhooks, their usage, and the platforms that are offering this service. With the rise of DevOps, software development has changed and organizations want to incorporate only the best practices to level up. Webhooks do exactly the same, and now you can enjoy the benefit of these services on the cloud platform as well.