Introduction

JSLab is a fast, native JavaScript and TypeScript scratchpad for macOS. You open a tab and type, and JSLab runs your code a moment after you stop. Every result, log and error appears in the output panel, tagged with the line that produced it. There’s no project to set up and no build step.

Your code runs in a separate process, so an infinite loop or a crash never takes the editor down with it. Tabs are saved on your Mac, and JSLab has no telemetry and no crash-reporting service.

Start here

1. Install JSLab and open it for the first time.
2. Learn JSLab: eight short steps with videos, then every feature, each with an example to run.
3. Write your first tab: run code, read the output and manage tabs.
4. Learn how the free trial and license work: 14 days free, then a one-time key.

Browse the docs

• Writing codeAuto Run, Auto Log, magic comments, logpoints, the output panel, formatting and snippets.
• RuntimesBun, Browser, and Browser & Node APIs, plus the Web View for React, Vue, Solid and Angular.
• Packages and environmentInstall npm packages, give a tab a working directory and set environment variables.
• Ask AIAsk about the code in your tab with Ollama, OpenAI, Anthropic or Google Gemini.
• CustomizingThemes, fonts, zoom and layout, keybindings, the command palette and every setting.
• ReferenceEvery command and shortcut, the jslab CLI, troubleshooting and translating.