Suggestions appear as you type. Use the up and down arrows to choose one and Enter to open it.

This page's audience our own tag's counts — open to see them
–Visits
–Page views
–Clicks to vendors
–Time on page
–Reading now
Clicks to vendors, by tool
  • –
Top countries
  • –
Devices
  • –

– · visits, page views and clicks counted by our own tag, which counts more than our checked analytics; every figure rounded down · how we count

Head-to-head · Code Transpilers

Google Web Toolkit vs Scala.js

  • Updated Oct 2026
  • Both researched from official sources
  • 4 checks side by side
Higher score Google Web Toolkit #6 in Code Transpilers 8.5/10 Free plan Free plan✓ 2 of 4 features Visit GWT
Scala.js #8 in Code Transpilers 8.3/10 Open source ✓ 3 of 4 features Visit Scala.js

Google Web Toolkit leads on 0 checks, Scala.js on 0, and 4 are even. Who comes out ahead on the 4 yes/no, price and count checks where we have data for both products. The editor score weighs everything else too.

Our verdict

  • Highest scoreGoogle Web Toolkit · 8.5/10
  • Free planonly Google Web Toolkit
  • Most featuresScala.js · 3 of 4

Google Web Toolkit scores higher on our rubric for code transpilers: 8.5 against 8.3 out of 10; our editors rank them #6 and #8.

On conversion mode, Scala.js gives you Both where Google Web Toolkit offers Source-to-source.

Google Web Toolkit is the better fit for java teams building browser applications. Scala.js is the better fit for scala teams building JavaScript applications.

  • Google Web Toolkit fits best

    Java teams building browser applications

  • Scala.js fits best

    Scala teams building JavaScript applications

Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.

Side by side

Feature Google Web Toolkit 8.5/10 Visit ↗ Scala.js 8.3/10 Visit ↗
At a glance
Editor score 8.5 8.3
Ranking #6 in Code Transpilers #8 in Code Transpilers
Best for Java teams building browser applications Scala teams building JavaScript applications
Pricing model Free Free
Starting price Free plan Open source
Free plan ✓ (best) Not checked yet
Free trial — —
Deployment Self-hosted Self-hosted
Support Community, Docs Community, Docs
Built for Solo, Small business, Mid-market, Enterprise Solo, Small business, Mid-market, Enterprise
Features Google Web Toolkit 2/4 · Scala.js 3/4
Syntax-version conversion Not checked yet Not checked yet
Intermediate output Not checked yet ✓ (best)
CLI access ✓ ✓
API access ✓ ✓
Specs
Source languages Not checked yet Not checked yet
Target languages Not checked yet Not checked yet
Conversion mode Source-to-source Both
Our review
Pros
  • Compiles client-side Java into optimized JavaScript
  • Includes Java APIs, UI widgets and JsInterop
  • Offers code splitting, debugging modes and JUnit testing
  • Incremental compilation supports iterative Scala-to-JavaScript builds
  • Dead-code elimination and linking help shape JavaScript output
  • Interop includes JavaScript libraries, React, AngularJS, Node.js, and Vite
Cons
  • Requires Java development for client-side application code
  • Uses a self-hosted SDK rather than a hosted service
  • Support is centered on community resources and documentation
  • Requires Scala source code, so it is not a general-purpose transpiler
  • Project workflows are commonly managed through build tools such as sbt
  • Support is through community channels and documentation
Our verdict

Google Web Toolkit is an open-source toolkit for building browser-based applications with client-side Java. Teams write application code in Java and compile it into JavaScript for web browsers. Its intended audience is Java teams that want…

Read the review →

Scala.js brings Scala into JavaScript application development by compiling Scala source files into JavaScript. It is aimed at teams that want to write application logic in Scala while targeting browsers, Node.js, or JavaScript modules. The…

Read the review →
  1. Google Web ToolkitCode Transpilers 8.5Free plan
  2. Scala.jsCode Transpilers 8.3Open source

Strengths and trade-offs

  • Google Web Toolkit — where it wins

    • Compiles client-side Java into optimized JavaScript
    • Includes Java APIs, UI widgets and JsInterop
    • Offers code splitting, debugging modes and JUnit testing

    Where it doesn't

    • Requires Java development for client-side application code
    • Uses a self-hosted SDK rather than a hosted service
    • Support is centered on community resources and documentation

  • Scala.js — where it wins

    • Incremental compilation supports iterative Scala-to-JavaScript builds
    • Dead-code elimination and linking help shape JavaScript output
    • Interop includes JavaScript libraries, React, AngularJS, Node.js, and Vite

    Where it doesn't

    • Requires Scala source code, so it is not a general-purpose transpiler
    • Project workflows are commonly managed through build tools such as sbt
    • Support is through community channels and documentation
  • Google Web Toolkit8.5/10 · Free plan

    A Java-based route to browser applications, with compilation, widgets and testing tools.

    Visit GWTFull verdict →
  • Scala.js8.3/10 · Open source

    An open-source Scala-to-JavaScript toolchain with incremental builds and JavaScript interoperability.

    Visit Scala.jsFull verdict →

More comparisons

All code transpilers comparisons → · Full ranking →

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Last updated · How we research and update