Webhook vs Server-Sent Events (SSE): The Difference
Server-Sent Events (SSE) stream a continuous one-way feed from a server to a client, usually a browser, over a single held HTTP connection with automatic reconnection. A webhook delivers a single discrete event from one server to another with no persistent connection. SSE is for pushing a live feed to a connected client; webhooks are for notifying a backend that a specific event happened.
Webhooks vs SSE at a glance
| Webhooks | SSE | |
|---|---|---|
| Connection | None; one request per event | One long-lived connection |
| Direction | Server to server | Server to connected client, one-way |
| Delivery unit | Discrete event | Continuous stream of messages |
| Reconnect / catch-up | Sender must retry | Built-in auto-reconnect with last-event-id |
| Typical use | Backend integrations | Live browser feeds: notifications, tickers, progress |
| Consumer | A backend endpoint | Usually a browser (EventSource) |
When to use each
Use webhooks when a backend needs to be told about an event and can receive an inbound request.
Use SSE when a connected client needs a steady stream of server updates and you do not need the client to send data back over the same channel.
How Hookdeck fits
SSE and webhooks sit at different layers: SSE gets updates to a user's screen, webhooks get events between services. If your service receives webhooks and then fans them out to browsers over SSE, the webhook ingestion layer is the part that needs durability. Hookdeck handles that ingestion with queuing, retries, and replay so nothing is lost before it reaches your stream. See the Event Gateway.
Related questions
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