Both webhooks and Server-Sent Events (SSE) deliver data in real time — but to completely different consumers.
The One-Line Distinction
Webhooks: server pushes to another server. SSE: server pushes to a browser. They solve different problems in different directions.
Comparison Table
| Dimension | Webhook | Server-Sent Events (SSE) |
|---|---|---|
| Direction | Server to your server | Your server to browser |
| Protocol | HTTP POST (one-shot) | HTTP/1.1 persistent connection |
| Consumer | Backend service | Browser / front-end |
| Authentication | HMAC signature | Cookies / JWT headers |
| Reconnection | Provider retries | Browser auto-reconnects |
| Firewall | Requires public endpoint | Outbound-only (always works) |
When to Use Webhooks
- Receiving events from third-party providers (Stripe, GitHub, Shopify)
- Triggering server-side processing on external events
- B2B integrations where both sides are backend services
When to Use SSE
- Pushing updates to a browser: live dashboards, notification feeds, progress indicators
- Streaming AI/LLM responses token by token
- Real-time features where WebSocket is overkill
They Often Work Together
A common pattern: a Stripe webhook fires when a payment succeeds, your server receives it, updates the DB, then emits an SSE event so the user's browser updates in real time.
// Webhook receiver (inbound from Stripe)
app.post('/webhooks/stripe', (req, res) => {
const event = verifyAndParse(req)
if (event.type === 'payment_intent.succeeded') {
updateDatabase(event.data)
sseEmitter.emit(event.data.customer_id, { type: 'payment_success' })
}
res.status(200).end()
})
// SSE endpoint (outbound to browser)
app.get('/events', (req, res) => {
res.setHeader('Content-Type', 'text/event-stream')
const listener = (data) => res.write(`data: ${JSON.stringify(data)}
`)
sseEmitter.on(req.user.id, listener)
req.on('close', () => sseEmitter.off(req.user.id, listener))
})Summary
- Receiving from third-party providers: Webhook
- Pushing to browsers: SSE
- Two-way browser communication: WebSocket