Stability & roadmap

What you can build on today, what's still moving, and what's experimental — June is 0.0.x, and this page says exactly where each piece stands.

Where June stands

June is 0.0.x preview. That doesn't mean everything is in flux — the core shape is settled and dogfooded (this site runs on it). It means the surface is still being drafted in places, and we'd rather tell you exactly where than imply a false 1.0.

The three tiers

tier what it means
Stable The shape is settled. Signatures may get minor tweaks, but the model won't change under you.
Changing Works today and is dogfooded, but the API is still being refined — expect renames and small breaks.
Experimental Opt-in and measured, but not the v0.1 default. Use it to look ahead, not to ship production on.

Stable

  • Routing & projections — file-based route(), the four surfaces (HTML / .md / .json / /mcp), content negotiation, and opt-in prerender.
  • Actions & the agent surface — defineAction() as a UI action and an MCP tool behind one run(input, ctx) gate; /mcp, /llms.txt, sitemap.xml, and the API catalog derived from the route graph.
  • Rendering — server-first RSC, explicit client islands, and browser-native navigation (Speculation Rules + View Transitions).
  • Styling — app/global.css (auto-linked) and CSS Modules, compiled with Lightning CSS.
  • Build & deploy — june build / june deploy, and the workers(), vercel(), and deno() adapters — all shipped; the demo app and this site run on them.

Changing

  • Data layer — resources, the ambient import { db }, and the Juno query/migration layer work and are dogfooded, but the surface is still being refined.
  • Auth — Better Auth is the blessed default; a first-class integration (session → ctx principal → /mcp scoping) is in progress. Bring-your-own works today.
  • Config & CLI — the june.config.ts shape and some CLI flags may still shift.

Experimental

  • Owned Rust+V8 runtime — boots in ~14 ms with a V8 snapshot and un-bundled dev. Measured, but the v0.1 default host is Bun/Node. See Runtime.
  • Server-reactive live RSC — server-driven live updates; exists and is measured, ships off by default.

What 0.0.x means

Pre-1.0, a minor or patch release may include a breaking change — that's the honest reading of semver below 1.0, not a surprise. We won't rename things for fun, and when a break lands we say so in the changelog with the migration. Benchmarks on this site are dev-machine numbers with published methodology and a named run behind each — re-run them, don't trust them.

How we signal changes

  • Changelog — every breaking change is listed with its migration.
  • This page — the tier table is updated as pieces graduate (Changing → Stable) or land (Experimental → default).
  • The site is the spec mirror — june.build is dogfooded on June, so if a doc claims something, the running site does it too.