Webhook vs. Websocket: What's the difference?

A webhook is a single HTTP request one server sends to another when an event happens, and the connection closes as soon as it is delivered. A websocket is a connection that stays open so both sides can send messages at any time. Webhooks fit server-to-server notifications; websockets fit interactive clients like browsers.

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Webhooks

Webhooks are sort of a reverse API, or server to server push notifications. It's how servers notify each other of events, and enable servers to update each other asynchronously in real time. They work by sending out an HTTP request to a specified webhook endpoint when an event is triggered. This makes webhooks ideal for integrating two applications. You can trigger actions in one app based on events in the other app.

Webhooks are very versatile, and how they are used varies greatly depending on the application. For example, they can be used to send notifications when a message is received, a payment is sent, or any other type of update. They are a way to get data from a third party back into your own system.

Websockets

Websockets are a type of communication protocol that provides full-duplex communication channels over a single TCP connection. While webhooks send information from one server to another, websockets create a two way communication channel.

You'll generally see websockets used to send communications from one part of an app to another. For example, many instant messaging applications use websockets to send and receive messages between the user and server. In the chat example, there would be a separate websocket connection for each user to send and receive messages.

When to use Webhooks (and when not to)

Webhooks are an extremely efficient communication method when appropriate. Webhooks are the perfect solution when you want one-way event driven communication between two servers.

A popular example of webhooks is Discord bots. A common use case for webhooks in Discord is a bot to automatically post in a channel when a specific Twitter account sends a tweet. This is an excellent use case for webhooks as you want the post to happen right away (real time), only when someone sends a tweet (event driven), Twitter doesn't need a response (one way), and only the bot needs to receive the information (one to one).

When to use Websockets (and when not to)

Websockets are very useful for interactive and real-time browser applications. A good example would be a navigation system. The client needs to receive directions from the server while the server needs the client's location to generate the directions.

If only the server ever sends, a socket is more machinery than the job needs, and server-sent events do the same work over a plain HTTP response. WebSocket vs SSE covers that choice.

Choosing between webhooks and websockets

	Webhooks	Websockets
Connection	One short HTTP request per event	One connection held open
Direction	Sender to receiver, one way	Full duplex, both directions
Who receives	Another server, at a public URL	A connected client, usually a browser
Cost grows with	Number of events	Number of concurrent clients
If the receiver is down	The sender retries	The message is lost unless you add a queue
Typical use	Payment succeeded, build finished, repo pushed	Chat, shared cursors, live dashboards

The two are not alternatives so much as answers to different questions. Ask who is on the other end. A browser that needs to both send and receive during a session wants a websocket. A customer's backend that needs to know a payment settled wants a webhook, because holding a socket open to every customer forever, and losing events whenever one of them redeploys, is a worse deal than a retried HTTP request. Plenty of products run both: websockets for the live UI, webhooks for the integrations. Svix handles the webhook side, with retries, signatures, and delivery logs. Webhooks vs server-sent events compares the third option.