Browse free open source JavaScript Compilers and projects below. Use the toggles on the left to filter open source JavaScript Compilers by OS, license, language, programming language, and project status.

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  • 1
    Google Closure Compiler

    Google Closure Compiler

    A JavaScript checker and optimizer

    Closure Compiler is a production-grade JavaScript optimizer and checker that parses JS, analyzes it, removes dead code, rewrites and minifies what remains, and emits faster, smaller bundles. Beyond minification, it performs advanced optimizations such as inlining, property collapsing, type-guided rewrites, and cross-module motion, often yielding substantial load-time wins. It includes a strong static checker that validates syntax, variable references, and type annotations (Closure types or JSDoc), catching bugs early and enabling aggressive transformations safely. The ecosystem provides a Java implementation, npm/JS builds, and documentation for integrating in modern toolchains. Closure Compiler has been used extensively at scale within Google and by the broader community, proving its robustness on very large codebases. Companion repositories track npm packaging and a JS-only variant for environments where running Java is undesirable.
    Downloads: 0 This Week
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  • 2
    Grain

    Grain

    The Grain compiler toolchain and CLI, home of the modern web staple

    Grain is a new language that puts academic language features to work. Enter the future. Grain compiles directly to WebAssembly, taking full advantage of its speed and efficiency. No runtime type errors, ever. Every bit of Grain you write is thoroughly sifted for type errors, with no need for type annotations. Grain has its roots in functional programming, but is flexible enough to accommodate different programming styles for various applications. Grain aims to modernize innovative features from functional and academic programming languages and bring them to the masses. Many languages have had wonderful ideas, but they have ultimately been dismissed as esoteric or too difficult to learn and, consequently, have struggled to rally a large community around them. Grain hopes to bring new life to these ideas and present them in an accessible form that’s easy to use and understand.
    Downloads: 0 This Week
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  • 3
    Hogan.js

    Hogan.js

    A compiler for the Mustache templating language

    Hogan.js is a 2.5k JS templating engine developed at Twitter. Use it as a part of your asset packager to compile templates ahead of time or include it in your browser to handle dynamic templates. If you're developing with Node.js, just use NPM to add the Hogan package. Hogan.js was developed against the mustache test suite, so everything that holds true for templates is also the case for hogan.js. That means you get variables, sections, lambdas, partials, filters, and everything else you've come to expect from mustache templating, only much, much faster. Use hogan.compile() to precompile your templates into vanilla JS. It's best to serve your templates precompiled whenever you can (rather than the raw templates), as parsing is the most time consuming operation. Once compiled, call the render() method with a context and optional partials object. If supplying partials, you can compile them ahead of time, or pass string templates.
    Downloads: 0 This Week
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  • 4
    JS/CC LALR(1) Parser Generator

    JS/CC LALR(1) Parser Generator

    A LALR(1) Parser Generator for JavaScript written in JavaScript

    JS/CC is a parser generator for JavaScript/ECMAScript, which is entirely written in ECMAScript itself. It produces LALR(1) parsers with integrated lexical analyzers. JS/CC can run as a website or be invoked from a console, and runs on several platforms.
    Downloads: 0 This Week
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  • 5
    JSGold is a GOLD Parser Engine in C++ for generating context-free grammar parsers in javascript.
    Downloads: 0 This Week
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  • 6
    This is an Eclipse plugin based on JSMin Javascript minifier. It adds an Ant task called jsminify that copies Javascript files and minifies them while copying, thus leaving the sources intact.
    Downloads: 0 This Week
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  • 7
    This is a JavaScript to Scheme translator written entirely in Scheme. Currently tested only with Guile
    Downloads: 0 This Week
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  • 8
    JavaScriptFlash: Compiling JavaScript to SWF JavaScriptFlash is a web-based platform to support the JavaScript web programmers to develop Flash applications in JavaScript. It compiles the JavaScript code following certain rules into a Flash SWF file
    Downloads: 0 This Week
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  • 9
    Lebab

    Lebab

    Turn your ES5 code into readable ES6

    Turn your ES5 code into readable ES6. Lebab does the opposite of what Babel does. Lebab transpiles your ES5 code to ES6/ES7. It does exactly the opposite of what Babel does. Convert your old-fashioned code using the lebab cli tool, enabling a specific transformation. The recommended way of using Lebab is to apply one transform at a time, read what exactly the transform does and what are its limitations, apply it to your code and inspect the diff carefully. Transforms can be applied with relatively high confidence. They use pretty straightforward and strict rules for changing the code. The resulting code should be almost 100% equivalent to the original code. Transforms should be applied with caution. They either use heuristics that can't guarantee that the resulting code is equivalent of the original code, or they have significant bugs which can result in breaking your code.
    Downloads: 0 This Week
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  • 10
    Mint

    Mint

    A refreshing programming language for the front-end web

    Mint has all the tools you need to write error-free, easily readable, and maintainable applications in record time. In Mint you can style elements directly with CSS using style blocks. Inside a style block, you can nest as many sub selectors and media queries as you like. Interpolate any Mint expressions in any value using the interpolation syntax. You can even use if and case expressions inside any block to apply styles conditionally. In Mint a store contains and manages some data. Stores are globally accessible and can be connected to components. When the data in a store changes the connected components are re-rendered. In Mint routing is a language feature instead of a library. Routes can be defined in a routes block, with support for typed path parameters. The runtime handles clicks on anchor tags and navigates in a smart way so you don't have to. You can inline any JavaScript code easily by using bacticks.
    Downloads: 0 This Week
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  • 11
    Multimethods for .NET: Makes multi-methods available to *any* language that targets .NET - C#, VB.NET, JScript.NET, Managed C++ and the rest! Uses .NET dynamic assemblies and shows how to generate dynamic .NET types and IL at runtime.
    Downloads: 0 This Week
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  • 12
    NJS is an independent implementation of the JavaScript language developed by Netscape and standardized by ECMA. It is designed to be re-entrant, extendible, fast, and programmable.
    Downloads: 0 This Week
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  • 13
    Narrative JavaScript is a small extension to the JavaScript language that enables blocking capabilities for asynchronous operations. This makes writing asynchronous code sequences easier and increases code readability.
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  • 14
    Online-GCC is an online integrated development environment (IDE) based on PHP technology. Any software developer would be able to design embedder projects for microcontrollers with or without of greater or smaller complexity, using only a Web navigator.
    Downloads: 0 This Week
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  • 15
    Pyjamas is a python to Javascript compiler, Widget set, Framework and Toolkit for Application development that runs on Web browsers. The developer need not know anything about AJAX: all the AJAX tricks, for all major browsers, are entirely taken care of.
    Downloads: 0 This Week
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  • 16
    Abacus Technologies Relational XQuery is an XQJ compatible XQuery processor that provides the ability to execute XQuery against both relational and XML data sources. Relational data can be transformed to any XML schema using XQuery's powerful features.
    Downloads: 0 This Week
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  • 17
    Rev = Really Easy Validation - write your form validation code once in this simple and powerful language that generates code for JavaScript, Perl, PHP, and Java. With Rev you get server side and client side data validation with no duplicated code.
    Downloads: 0 This Week
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  • 18
    RockScript is the world's smallest Java-based JavaScript interpreter, runs smoothly in any J2ME phones. The binary size of core engine including native objects/methods is less than 25K (obfuscated & JAR'ed). It can be integrated into any J2ME apps.
    Downloads: 0 This Week
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  • 19
    Picture Gallery viewable with HTML web browsers. All dynamics is implemented at client-side in JavaScript. This approach is useful when the server side is able to provide only static contents, or if the gallery is stored on CDROM or other media.
    Downloads: 0 This Week
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  • 20
    Schism

    Schism

    A self-hosting Scheme to WebAssembly compiler

    Schism is an experimental compiler that translates Scheme programs into WebAssembly, allowing Scheme code to execute in both browser environments and server platforms like Node.js. Developed initially by Google researchers, the project was designed to explore the intersection of functional programming and WebAssembly’s low-level efficiency. Schism supports a subset of the R6RS Scheme standard and is self-hosting, meaning that the compiler itself is written in and compiled by Schism. Its architecture demonstrates advanced compiler design techniques such as staged compilation and snapshot-based bootstrapping. The project focuses on leveraging WebAssembly’s experimental capabilities, including reference types and tail calls, to test the limits of language portability and runtime performance. Though no longer actively maintained, Schism remains a valuable example of how high-level languages can be mapped to WebAssembly and offers insights into language implementation.
    Downloads: 0 This Week
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  • 21
    Silis OS is a online based operating system which will allow users to access their files and programs from any where in the world.
    Downloads: 0 This Week
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  • 22
    Smee allows ECMAScript to be used as an extension language for Smalltalk applications.
    Downloads: 0 This Week
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  • 23
    SuperClass is a JavaScript pre-processor/interpreter object, designed to facilitate class-based OOP in JavaScript. NOTE: Project is closed. Replaced by: http://sourceforge.net/projects/jsclass
    Downloads: 0 This Week
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  • 24
    SuperWikia Alpha Codebase 1.1

    SuperWikia Alpha Codebase 1.1

    SuperWikia: The Runtime/Realtime Environment for Codesmiths

    The SuperWikia Alpha 1.0 application is an IDE specifically developed for 3D and graphic content. Its built upon the Unity foundation and incorporates various libraries from Komodo IDE, wxDevC++, CodeBlocks, QT Creator and other applications. Its Realtime purpose is an IDE (codesmith developer access), its Runtime (U/I) function is as a space building simulator, operating in conjunction with the SuperWikia 'Navigator' user interface to simulate space economics and fleet operations. It allows users (known as 'data fleet navigators' or DFN's) to compete in tourneys over vast regions known as 'expanses' and to create envoys that manage onsite and offsite stations. Using additional SuperWikia components, users may enhance their experience with plugins and 'dataplates' that help build the Runtime environment. Codesmiths (SuperWikia Alpha developers) can also build on top of the codebase using 'transcribes', acronym/algebraic encodes that differentiate codesmith works.
    Downloads: 0 This Week
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  • 25
    Traceur

    Traceur

    Traceur is a JavaScript.next-to-JavaScript-of-today compiler

    Traceur is a JavaScript.next-to-JavaScript-of-today compiler that allows you to use features from the future today. Traceur supports ES6 as well as some experimental ES.next features. Traceur's goal is to inform the design of new JavaScript features which are only valuable if they allow you to write better code. Traceur allows you to try out new and proposed language features today, helping you say what you mean in your code while informing the standards process. JavaScript's evolution needs your input. Try out the new language features. Tell us how they work for you and what's still causing you to use more boilerplate and "design patterns" than you prefer. You can use some language features right now and even try it out in your browser here. Just type in some code and see what Traceur produces.
    Downloads: 0 This Week
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