JSCR logo JSCR
Live inline execution · 10 languages · Free to use

Type code.
See results, live.

JSCR runs your code the moment you stop typing — right inside VS Code, next to every line. No run button, no terminal switching, no context loss. JavaScript & TypeScript, plus eight more languages.

Get it on the Marketplace See how it works
Zero config Dormant when off Free — incl. commercial use
Why JSCR

A scratchpad that thinks as fast as you do

Every top-level expression is evaluated and reported next to its line — in real time, as you type.

Live inline evaluation

Every expression is reported beside its line in real time. Stop typing for 300 ms — it runs. That's the whole workflow.

File Mode + Scratch Mode

Run any .js/.ts file against your workspace's node_modules, or spin up persistent scratch snippets that survive restarts.

AI-assisted fixes

Hit a runtime error? Send it to OpenRouter and preview a two-column diff before you accept a single character. Bring your own key.

Dormant when off

Zero background processes when the panel is closed. JSCR only works while you're watching — nothing lingers, nothing polls.

Theme-native output

Panel colors are pulled straight from your active VS Code theme — never hardcoded. It looks like it always belonged there.

Truly polyglot

First-class Python, Java, Go, Rust, C#, C++, Ruby and Groovy alongside JS/TS — each auto-detected and running live.

Polyglot engine

Ten languages, one live panel

Each toolchain is auto-detected on startup and cached, so launches stay instant. A language only appears when a supported version is found — everything else keeps working regardless.

JavaScriptJavaScriptNode 17+
TypeScriptTypeScript3.8+
PythonPython3.7+
JavaJavaJDK 11+
GoGo1.11+
RustRust1.39+
C#C#.NET 6+
C++C++14+
RubyRuby2.5.1+
GroovyGroovy2.5+

Compiled languages (Go, Java, Rust, C#, C++) re-compile and run live on an idle debounce — never mid-keystroke. Turn it off per language to run on demand.

Program input

Interactive programs that never hang

For code that reads stdin — Java Scanner, Python input(), Go fmt.Scan — type your input ahead of time in the Program Input box.

  • One value per line, remembered per snippet.
  • JSCR feeds it in, then closes stdin — a read past your input fails fast instead of waiting for a human.
  • The live re-run never blocks on a prompt again.
Program Input
Alice
30
// java Scanner reads →
Hello Alice, age 30
Share a run

From "let me screenshot this" to "here's the code"

The panel's Save run as… button exports your snippet and its output in one click.

  • Markdown — a code fence + output fence, ready to paste into a GitHub issue or PR.
  • Standalone HTML — a self-contained, theme-coloured page you can drop into any doc or chat.
run.md
```js
console.log('winner:', top)
```
Output
winner: linus
How it compares

Everything you liked, none of the walls

Capability JSCR RunJS Quokka
Runs inside VS Code✓separate app✓
Live inline evaluation✓✓paid tier
Persistent scratch snippets✓✓✕
Uses workspace node_modules✓partial✓
10-language polyglot engine✓✕✕
AI-assisted fixes (BYO key)✓✕✕
Free — including commercial✓✕partial

Install JSCR in one click

Open the Extensions view, search JSCR, hit install — then press Ctrl+Shift+J.

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