How It Works

Kiln operates in two phases: Build-Time Compilation and Runtime Initialization.

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Phase 1: Build-Time Compilation

When you run kiln:

Framework Build (next build / astro build)
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1. Framework Auto-Detection
   • Discovers adapter (Next.js, Astro, etc.)
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2. Asset Mapping & Dead-Code Pruning
   • Traverses standalone output & static assets
   • Prunes dead build artifacts (sourcemaps, dev bundles, Webpack machinery)
   • Compresses text server chunks >= 8KB with Level-1 Gzip
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3. Standalone Entrypoint Generation
   • Generates assets.generated.js with embedded file imports
   • Generates server-entry.js with dynamic runtime loader hooks
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4. Native Bun Compilation
   • Executes `bun build --compile --production --minify`
   • Emits single executable binary

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Phase 2: Runtime Lifecycle

When the compiled binary is executed on a server:

1. Cold Start (First Boot):
   • Checks .kiln-extracted for a valid SHA-256 build stamp.
   • If not found or changed, unpacks embedded runtime assets into baseDir (or KILN_RUNTIME_DIR).
   • Writes the new build stamp.
2. Warm Start (Subsequent Boots):
   • Reads the build stamp and matches the embedded hash.
   • Skips disk extraction completely and starts the HTTP server in 0ms.
3. HTTP Server Execution:
   • Delegates request handling to the framework’s native production engine (startServer for Next.js, entry.mjs for Astro).