Architecture

How Resuma turns Rust components into instantly-interactive HTML without hydration.

LIVE

Resumability pipeline

1. SSR render

The resumability promise

Traditional SSR: render on server → hydrate on client (re-run all components). Resuma: render once → serialize state → client resumes only what the user touches.

Server (Rust)  ──HTML + payload──►  Browser
render components              parse resuma/state + loader.js (907 B gzip)
serialize signals              first click → core.js (~4 KiB gzip)
                               lazy-import handler chunks

Pipeline of one click

view! expansion — closure → rs2js (in resuma-macros) → HandlerRef in HTML
SSR — walk View tree, emit data-r-on:* attributes + JSON payload
Runtime — document listener, lazy fetch handler chunk, update signals

Payload format

<script type="resuma/state" id="resuma-state">
{"signals":[...],"handlers":{},"lazy_chunks":["Counter"],"islands":[],"actions":[]}
</script>
<script type="module" src="/_resuma/loader.js"></script>

Component boundaries

Each #[component] emits <resuma-boundary data-r-chunk="Counter"> for viewport prefetch. Handler JS loads from /_resuma/handler/Counter.js — not inlined in the payload.

Crates

Crate / module	Role
`resuma`	Single runtime crate — depend on this only
`resuma::core`	Signals, View, resumability primitives
`resuma::ssr`	HTML rendering + streaming chunks
`resuma::server`	axum HTTP, /_resuma/* endpoints
`resuma::flow`	FlowApp, pages, loads, submits
`resuma::exec`	Resuma OS — workers, queue, scheduler, graphs
`resuma-flow`	Ops UI — dashboard, graph widgets (optional crate)
`resuma::router`	File-based page scanner
`resuma-macros`	view!, #[component], #[load], #[submit] (proc-macros)

Resumability vs hydration

Aspect	Classic SSR + hydration	Resuma
Client after load	Re-run components	Resume handlers only
Initial JS	App bundle grows with UI	907 B loader + ~5 KiB first interaction + lazy chunks
Static pages	Often still ship framework JS	Zero client JS

HTTP endpoints

Core (all apps)

GET /_resuma/runtime.js — client bootstrap
POST /_resuma/action/:name — #[server] RPC
POST /_resuma/submit/:name — #[submit] forms
GET /_resuma/handler/:chunk — lazy handler JS

Resuma OS (when exec is enabled)

Full route list →

POST /_resuma/worker/:name — start execution graph
POST /_resuma/queue/:name — durable enqueue
GET /_resuma/graph/:id/events — SSE event stream
GET /_resuma/status · GET /_resuma/metrics — ops / Prometheus