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Head-to-head · Code Transpilers

SWC vs Scala.js

  • Updated Oct 2026
  • Both researched from official sources
  • 4 checks side by side
Higher score SWC #2 in Code Transpilers 9.2/10 Free plan Free plan✓ 0 of 4 features Visit SWC
Scala.js #8 in Code Transpilers 8.3/10 Open source ✓ 3 of 4 features Visit Scala.js

SWC 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 scoreSWC · 9.2/10
  • Free planonly SWC
  • Most featuresScala.js · 3 of 4

SWC scores higher on our rubric for code transpilers: 9.2 against 8.3 out of 10; our editors rank them #2 and #8.

SWC is the better fit for fast JavaScript and TypeScript build pipelines. Scala.js is the better fit for scala teams building JavaScript applications.

  • SWC fits best

    Fast JavaScript and TypeScript build pipelines

  • Scala.js fits best

    Scala teams building JavaScript applications

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Side by side

Feature SWC 9.2/10 Visit ↗ Scala.js 8.3/10 Visit ↗
At a glance
Editor score 9.2 8.3
Ranking #2 in Code Transpilers #8 in Code Transpilers
Best for Fast JavaScript and TypeScript build pipelines 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
Integrations 6 integrations 5 integrations
Built for Solo, Small business, Mid-market, Enterprise Solo, Small business, Mid-market, Enterprise
Features SWC 0/4 · Scala.js 3/4
Syntax-version conversion Not checked yet Not checked yet
Intermediate output Not checked yet ✓ (best)
CLI access Not checked yet ✓ (best)
API access Not checked yet ✓ (best)
Specs
Source languages Not checked yet Not checked yet
Target languages Not checked yet Not checked yet
Conversion mode Not checked yet Both
Our review
Pros
  • Compiles JavaScript and TypeScript, with minification and source maps
  • Supports tree shaking, dead-code elimination, and shared-dependency chunking
  • Integrates with Next.js, webpack, Rspack, Jest, Parcel, and Deno
  • 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
  • The spack bundler is documented as slated for removal in v2
  • Bundling depends on spack, so its future path warrants attention
  • Support channels are community 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

SWC is an open-source, Rust-based compiler and build tool for JavaScript and TypeScript projects. It transforms modern code into browser-compatible output and offers minification, source maps, tree shaking, and bundling through its spack…

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. SWCCode Transpilers 9.2Free plan
  2. Scala.jsCode Transpilers 8.3Open source

Strengths and trade-offs

  • SWC — where it wins

    • Compiles JavaScript and TypeScript, with minification and source maps
    • Supports tree shaking, dead-code elimination, and shared-dependency chunking
    • Integrates with Next.js, webpack, Rspack, Jest, Parcel, and Deno

    Where it doesn't

    • The spack bundler is documented as slated for removal in v2
    • Bundling depends on spack, so its future path warrants attention
    • Support channels are community 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
  • SWC9.2/10 · Free plan

    An open-source compiler with minification and bundling for JavaScript and TypeScript workflows.

    Visit SWCFull 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