> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kiln.land/llms.txt
> Use this file to discover all available pages before exploring further.

# Reference

> Platforms, runtimes, files and channels — the facts behind the v1.0.0 binary.

## The binary

Kiln ships as a 22 MB binary for macOS, Linux and Windows. In containers, the image is 22 MB and cold start is 11 ms.

## What it runs

| Target | How it runs | Support |
| - | - | - |
| JavaScript | Runs as-is. ES2026 and stage-3 syntax, no build step. | native |
| TypeScript | Types stripped in the runtime, checked by `kiln check`. | native |
| JSX / TSX | Compiled in place. No plugin, no transform config. | native |
| WebAssembly | Core modules and the component model, WASI 0.3 preview 2. | native |
| WAT | Text format compiles inside the runtime, source maps included. | native |
| Rust, C, C++, Zig | Any `wasm32-wasip2` target runs in the same process. | wasm |
| Go, Swift | Through the WASI preview 2 target. No cgo, no bridge. | wasm |
| Python | CPython built for WASI. Import numpy from a wheel cache. | preview |
| Hugo | Templates, shortcodes and content rendered natively. | native |
| HTML, CSS, Markdown | Served and bundled. Tailwind and PostCSS read from config. | native |
| SQL | Embedded client for Postgres, MySQL and a local libSQL file. | native |

## Files Kiln reads

* `package.json` — dependencies, scripts and workspaces
* `tsconfig.json` — compiler options
* `node_modules` — your installed tree
* npm, yarn and pnpm lockfiles — dependency versions
* eslint config — rules for `kiln lint`
* `Makefile` — targets for `kiln task`
* `kiln.toml` — task definitions for `kiln task`

Each file stays in place. There is no migration step and no config file to write first.

## Isolation

Every route, worker and test file runs in its own isolate with its own heap. A panic in one is a stack trace and a restart, not a dead process.

## Channels

You can pin a channel per project. Rolling back is `kiln pin`, not a reinstall.

| Channel | Cadence |
| - | - |
| stable | ships every two weeks |
| lts | freezes once a year |
| nightly | everything the day it lands |

Stable ships with a two-year support window.

## Verified numbers

| Metric | Kiln | Comparison |
| - | - | - |
| Hot reload | 8 ms | Node 800 ms |
| First install | 6.9 ms | bun 1.41 s, npm 18.12 s |
| Cold start | 4 ms | Node 50 ms |
| Install memory | 9 MB | npm 698 MB |

Every number comes out of `kiln bench` on the reference bench: Linux x64, AMD EPYC 9R14, 64 vCPU, a T3-stack app with 25 direct dependencies and 220 packages in the lockfile, `node_modules` removed before each run. Install numbers are medians of 3 runs, hot reload medians of 20. Node 26.12.0, Bun 1.4.3, Deno 2.9.7, npm 12, pnpm 11.21 and yarn 1.22 run at defaults.

<Card title="Every command" icon="list" href="/cli">
  The rack, one entry per command.
</Card>


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