Static and SSR fidelity
Static site and SSR targets share the same authored widget tree as native targets, but they do not have every native runtime capability. The right model is progressive fidelity: use typed Fission primitives, let the site shell lower what can be represented in HTML/CSS, and keep interactive host work explicit.
What lowers well
Fission primitive | Static site | SSR |
|---|---|---|
Length points, percent, viewport units, clamp | CSS lengths and clamp() where possible | CSS lengths and clamp() where possible |
Responsive viewport cases | CSS/media-rule style branch selection | CSS/media-rule style branch selection |
Responsive container query | Lowered when static constraints can express it | Lowered where request/runtime supports container sizing |
GridTrack points/fr/auto/minmax/repeat/auto-fit | CSS grid tracks | CSS grid tracks |
Solid fills, gradients, borders, radius, shadows | CSS paint | CSS paint |
Packaged fonts | Emitted as font assets where configured | Emitted as font assets where configured |
Backdrop blur | CSS backdrop-filter if supported by browser | CSS backdrop-filter if supported by browser |
What needs care
Portals, animations, jobs, services, and capabilities still need a runtime. Static output can describe the initial state; it cannot perform user-triggered host work without a client runtime or island.
Prefer declarative layout primitives for pages that must statically render well. Use imperative viewport logic only when the result can still be evaluated by the target shell.
Fission
A cross-platform, GPU-accelerated user interface framework for Rust. MIT licensed.
Copyright (c) 2026 Fission
Ready to use today. Widget APIs are expected to remain stable; some runtime and shell APIs may change before 1.0.0.
Fission 0.9.2