In modern times, various technologies are used to establish a connection between the servers and clients (end users). Two such technologies are WebSockets and Webhooks.

Short Overview

WebSocket
It is a communication protocol to connect with servers of any website or mobile application. By using this, clients (such as a browser) can establish a single long-lived connection with the server. It allows the client and the server to efficiently exchange data. Moreover, it is bidirectional where both the client and server can send and receive data.
You can read our previous blog, for more information.

Webhook
This is a useful method of communication between two servers. One server sends a particular data package about an event that happened to the other server. This data can now be used for other purposes. Unidirectional by nature, where the sender notifies the receiver.
For more information, feel free to read our first blog post.

Real-Time vs. Event-Driven

WebSockets are real-time, suitable for instant updates and interactive applications.
Webhooks are event-driven, used to notify external systems about specific events once that event has occurred.

Connection Type
WebSockets are persistent, long-lived connections.
Webhooks are stateless, short-lived, and initiated by the sender.
We can discuss in more detail about stateless, stateful and persistent connections on a future blog.

What Should You Choose?

Depending on the project requirements and the technology’s use, more questions need to be answered before choosing to implement a WebSocket or a Webhook.
Do you need to automate a task based on specific events only? If yes, then Webhook is a good choice.
Do you need real time communication? If yes, then WebSocket is the best route.
Do you want to make the connection between server and the client persistent? If yes, then again, a WebSocket would be the best option.
Do your endpoints allow asynchronous operation? If yes, you can use Webhooks and it is asynchronous by nature.
Does your project need rapid complex interactivity? If yes, WebSocket does complex interactivity with low latency.
Do you have to customize the data on a specific event before sending it to an endpoint? Webhooks are highly customizable.

See below for further details on all the above questions.

For and Against

Pros for WebSocket

• Real time communication: Applications that require real time data updates that can be achieved by implementing Websockets. Websockets enable real time data exchange between server and client ( like browsers ).
• Low latency: The initial connection request to establish connection between browser and server is a bit large, after that all the data transfers between server and client are very light. Because these don't need to send all the data like HTTP requests on per request. It reduces the delay in websocket connection.
• Bi directional: To make an app interactive it is very important to share data between each other at the same time. Websocket allows bidirectional data transfer between the server and the client. So, each other can share data at any given time.

Cons for WebSocket

• Complexity: It is a bit more complex to implement Websockets than HTTP. Because it requires some additional work both at server and client side.
• State Management: To scale the websocket servers, we need to be careful about stateful Websocket connections. If state is not shared or managed between all the servers it will be not scalable at all.
• Not optimized for all kinds of data: Data like audio and videos is not suitable for websocket. The text based data is more preferable for websocket use case.

Webhook Pros

• Real time updates: Webhooks allow real time updates based on some events. This is important in many scenarios like data changes or some crucial update that happened which can be notified via webhook event to another server.
• Low cost: For getting updates about any particular event, the traditional way was to simply frequent polling or perform manual checks. However, if Webhook was implemented, then it only sends data when there is an actual update. This reduces the bandwidth cost like in other methods.
• Customizable: In many events users can define which event triggers Webhooks. And they can also specify the data structure before sending any data.

Webhook Cons

• Security: As mentioned in our first blog, webhook endpoints are commonly not exposed, this is because the developers think like they didn’t publicly share the endpoint. But in some cases these endpoints are exposed if unexpected security risks arise.
• Scalability: Managing a large number of endpoints with different kinds of events is challenging.
• Error on failure: If the Webhook system fails to deliver a request to the endpoint, there is a need to resend the request. For this custom implementation is required.