Realtime Transport · decision tool
WebSockets vs Server-Sent Events (SSE) — for your app, not in general
WebSockets or Server-Sent Events (SSE)? Scored on documented capabilities for your requirements — the honest fit comparison, with "No clear winner" when they're genuinely close.
Capabilities verified 2026-07-17 against official documentation · fit weights are our estimates (see methodology) · share the URL to share your configuration
As of Jul 2026, for this page's default requirements, Server-Sent Events (SSE) is the clear pick at 89% capability fit (WebSockets: 34%). This is a capability-fit decision, not a price ranking — StackSays does not invent a unified dollar comparison across these tools' incompatible billing units. Change any requirement below and the verdict recomputes.
Your requirements
The verdict updates as you change these. Share the URL to share your answers.
Clear pick
Server-Sent Events (SSE) (89% fit)
Ranked by capability fit
Server-Sent Events (SSE) vs WebSockets — the tradeoffs that decide it
- Serverless compatibility: Server-Sent Events (SSE) — Works on serverless — no persistent-connection server to run (documented constraint). WebSockets — Needs a long-lived connection that serverless functions can't hold — the classic 'websockets on serverless' problem.
- Simplicity: Server-Sent Events (SSE) — Few moving parts — simple to build and operate. WebSockets — More moving parts (connection lifecycle, scaling, reconnection) to own.
- Auto-reconnect: Server-Sent Events (SSE) — Built-in reconnection on drop (documented). WebSockets — You implement reconnection/heartbeat yourself.
- Direction match: Server-Sent Events (SSE) — One-way server → client is exactly this transport's shape. WebSockets — Two-way capable (more than you need for one-way).
When to pick WebSockets instead: when the lines above where it leads matter more to you than the ones where Server-Sent Events (SSE) leads. Change the inputs to see the ranking flip.
This is a capability-fit decision, not a price ranking — these tools bill in incompatible units (per-search vs per-RAM cluster vs per-PB scanned) and several publish rates only in their own calculators, so StackSays does not invent a unified dollar comparison. Every score above traces to a documented capability; see Data sources below.
At a glance
| Tool | Deployment | Open source | Verified |
|---|---|---|---|
| WebSockets | Self-hosted | Yes | 2026-07-17 |
| Server-Sent Events (SSE) | Self-hosted | Yes | 2026-07-17 |
Data sources
| Tool | Source | Verified |
|---|---|---|
| WebSockets | MDN WebSockets API (capabilities) | 2026-07-17 |
| Server-Sent Events (SSE) | MDN Server-Sent Events (capabilities) | 2026-07-17 |
A monitor re-checks these pages for changes; when a vendor moves a price, the date updates and every verdict recomputes.