Introduction

Kiln is an open-source universal compiler that transforms modern fullstack web applications into single, standalone native executable binaries using Bun.

The Problem with Traditional Web Deployment

Deploying fullstack JavaScript and TypeScript applications to servers, virtual machines, or minimal containers traditionally requires:

Large node_modules Directories: Shipping thousands of small files to production creates slow I/O, heavy container layers, and permission complexities.
Runtime Host Dependencies: Traditional deployments require a compatible JavaScript runtime and a correctly installed dependency tree on the target machine.
Complex Cold Starts: Starting dynamic servers from cold filesystems requires disk seeks across hundreds of dependencies before listening on ports.

The Kiln Solution

Kiln packages your framework build output, static assets, and runtime dependencies into one single binary executable (e.g. ./server or .\server.exe):

┌──────────────────────────────────────────────────────────┐
│                   Single Native Binary                    │
│                      (e.g. ./server)                     │
├──────────────────────────┬───────────────────────────────┤
│ • Embedded Static Assets │ (CSS, JS, Images, Fonts)      │
│ • Embedded Server Chunks │ (SSR routes, manifests)       │
│ • Embedded Runtime Deps  │ (node_modules, libraries)     │
│ • Standalone Runner      │ (Fast native runtime)         │
└──────────────────────────┴───────────────────────────────┘

Key Benefits

Zero Host Dependencies: Copy the single binary to any Linux, macOS, or Windows server and run it. No Node.js or npm install needed on the server.
Microsecond Cold Starts: Fast-path SHA-256 build verification skips extraction on restarts, enabling near-instant boot times.
Cross-Compilation: Build for Linux x64 or Linux ARM64 directly from your local machine using --target.
Universal Architecture: Clean FrameworkAdapter design supporting Next.js 16, Astro 7, and future fullstack frameworks.