jam

jam serves JavaScript and TypeScript files as HTTP routes with isolated per-request execution.

Usage

jam [flags] [scripts-dir]

Common Commands

# Serve scripts from ./scripts on port 3000
jam ./scripts

# Development mode with detailed error pages
jam --mode development ./scripts

# Use a config file
jam --config ./jamconfig.json ./scripts

# Enable PHP-style globals
jam --php ./scripts

For the complete CLI surface, run:

jam --help

Minimal Script

export default {
  fetch() {
    return new Response("Hello from Jam");
  }
};

Saved as scripts/app.ts, this route is available at /app.

Docs

• Introduction
• Getting Started
• Build a Real App
• Configuration
• Runtime APIs
• Templates
• Deployment

Development

jam has two entry points with different roles:

• bin/jam.js: Node-facing dispatch shim for npm usage.
• src/entry.ts: Bun runtime CLI entrypoint compiled into platform binaries.

For repeatable runtime engineering workflows, see the repo-local skills index: ../../skills/README.md.