Free and open first
Best Code Transpilers in 2026
When code needs to move between languages or syntax versions, a transpiler can convert it toward a different target. Compared on source and target languages, syntax-version conversion, and conversion mode, these tools also vary in whether they provide intermediate output. API and CLI access can shape how you use one in a development workflow; free-plan availability and the listed starting price provide additional context. SWC, Transcrypt, and Babel are among the entries to compare. Start with the languages and conversions you need, then weigh the available access methods and output details.
- 28 apps
- Research read 23 Sept 2026
- How the order is worked out
- 1
JSweet
Free plan Open source AndroidAPIiPhone+5JSweet gives Java developers a route to JavaScript output while working with JavaScript libraries and tools.
- 2
Babel
Free plan APILinuxMac+2Babel provides a free, plugin-based way to transform JavaScript, with CLI and browser-use options. Keep its type-checking limitation and production guidance in mind when planning a build workflow.
- 3
ClojureScript
Free plan LinuxMacSelf-hosted+2ClojureScript brings Clojure features and interactive development to JavaScript targets, with output that can use Closure Compiler advanced compilation.
- 4
Google Web Toolkit
Free plan ExtensionLinuxMac+2GWT combines Java development with browser-oriented compilation and a set of documented development tools.
- 5
Brython
Free plan AndroidiPhoneSelf-hosted+1Brython brings Python syntax and browser APIs together for interactive web pages, with several ways to load or deploy applications.
- 6
Cython
Free plan LinuxMacWindowsCython offers a route from Python-like source to compiled extension modules, with options for static types, C/C++ interoperation, and debugging.
- 7
- 8
CoffeeScript
Free plan APILinuxMac+2CoffeeScript provides a compile-to-JavaScript workflow with command-line and compiler API options. Check its runtime requirements and transpilation needs for the JavaScript features you plan to use.
- 9
J2ObjC
Free plan iPhoneLinuxMacJ2ObjC provides a way to bring Java non-UI code and tests into iOS projects. Its source-code requirement, platform prerequisites, and lack of shared UI support shape where it fits.
- 10
Kotlin/JS
Free plan LinuxMacWeb+1Kotlin/JS lets developers use Kotlin in browser and Node.js projects, with framework wrappers and multiple module formats.
- 11
js_of_ocaml
Free plan APILinuxWebChoose js_of_ocaml if you want to compile OCaml bytecode for browser or Node.js use, especially when Dune and its browser bindings fit your workflow.
- 12
Opal
Free plan LinuxMacWeb+1Opal offers Ruby-to-JavaScript compilation with interoperability and framework integrations.
- 13
Dart pub
Free plan LinuxMacWindowsPub covers dependency resolution, publishing, and offline use for Dart projects. Its publishing rules and limited-pattern secret checks are worth noting before releasing packages.
- 14
Scala.js
Free plan APILinuxMac+2Scala.js brings Scala typing and tooling to JavaScript development, with listed routes to interoperate with JavaScript libraries. Review the 1.22.0 compatibility note if upgrading from 1.21.x.
- 15
CodeTransEngine
Free plan APISelf-hostedCodeTransEngine provides a configurable backend for source-to-source translation with several algorithms, language-model inference options, and automated evaluation.
- 16
SWC
Free plan AndroidAPILinux+3SWC covers compilation and transformation needs with multiple integrations and package options, and it is free.
- 17
Transcrypt
Free plan LinuxMacSelf-hosted+2Transcrypt offers a way to write browser applications in Python while using JavaScript libraries and tools.
- 18
Kalai
Free plan Self-hostedChoose Kalai if you want to translate supported Clojure code for use in other languages and can work through its command-line tool.
- 19
SourceMeld
Free plan APISelf-hostedSourceMeld combines cross-language code search with AI-assisted source migration in a self-hosted package.
- 20
Vala
Free plan LinuxMacWindowsVala combines native compilation with GObject and GTK integration. Its listed stable long-term support version is 0.56.17, while the main branch remains under development.
- 21
Mitosis
Free plan APIWebMitosis provides a route from JSX components to a range of framework outputs, with CLI and configuration options for different build scopes.
- 22
Skulpt
Free plan WebPick Skulpt for browser-based Python learning or for adding Python execution to a webpage without server-side support.
- 23
Sucrase
Free plan APILinuxChoose Sucrase for development builds targeting modern JavaScript runtimes when its available transforms and integrations fit your project.
- 24
ReScript
Free plan LinuxWebReScript offers typed source development while retaining access to the JavaScript ecosystem.
- 25
TypeScript Playground
by TypeScript PlaygroundFree plan WebChoose TypeScript Playground for browser-based experiments, instruction, or sharing a configured code example.
#1Places #1, #2, #3, #4, #5 on this list can be bought by the makers of the software on it. See the price
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