RunJS

runjs · v4.0.4 • auto-updates

7.5

JavaScript playground that auto-evaluates as code is typed

Developer Tools macOS 12+ Homepage →

brew install --cask runjs

Compare with: vs. Electron Fiddle vs. WebStorm vs. Reactotron vs. .Net Runtime

30-day installs

90-day installs

385

365-day installs

Install trend

Trust Score 5/10

✗ Open source +0

✓ Active development +2

✗ Licensed +0

✓ Auto-updates +1

✓ Not deprecated +1

✓ Established (>1yr) +1

✗ Low installs +0

Version History

v4.0.4

today4.0.2→4.0.4

5d ago4.0.1→4.0.2

6d ago4.0.0→4.0.1

7d ago3.2.2→4.0.0

Review

Mar 11, 2026

RunJS is a JavaScript playground for macOS that provides instant feedback as you type, making it ideal for developers and learners who want to experiment with JavaScript code. It supports Node.js and browser APIs, offering a versatile environment for quick prototyping and testing.

RunJS is a JavaScript playground that evaluates code in real-time and supports Node.js and browser APIs.

Maturity: The project is mature with active maintenance and a strong community following.

Community: RunJS has been mentioned on Hacker News multiple times, with significant traction in 2019 and 2025. However, there is no discussion on Reddit.

Pros

+ Real-time code evaluation provides instant feedback for quick experimentation.
+ Supports both Node.js and browser APIs, making it versatile for different use cases.
+ Cross-platform availability (macOS, Windows, Linux) broadens its appeal.

Cons

- Some users have reported issues with autocomplete functionality on certain MacBooks.
- The project's license and language details are not specified, which could be a concern for some users.