Kalai

At a glance

• Editor score
  6.6 / 10
• Pricing
  Open source
• Best for
  Clojure developers targeting Rust, Java, or C++
• Paid from
  Free
• Intermediate output
  No
• Conversion mode
  Source-to-source
• Facts checked
  22 Sep 2026

• Where it wins

  • Generates Rust, Java, and C++ source from Clojure
  • Runs through the Clojure CLI with configurable source directories
  • Supports type metadata and multiple transformation passes

• Where it doesn't

  • Supports a subset of Clojure constructs
  • Requires self-hosted CLI use rather than API access
  • Documentation is the listed support channel

Our verdict on Kalai

Kalai is an open-source, source-to-source transpiler for Clojure developers who want to generate Rust, Java, or C++ code. Distributed as a Clojure library and command-line tool, it takes input and output directories for transpilation. Its fit is specific: teams already working in Clojure who need one of these three targets should find the scope relevant, while developers seeking a general-purpose converter or a hosted workflow should look elsewhere.

The language coverage is centered on a documented subset of Clojure rather than a claim of full-language conversion. Supported constructs include namespaces, functions, definitions, let bindings, atoms, and persistent data structures. Kalai maps namespaces to classes and functions to static functions, and supports type metadata and type aliases in generated code. Multiple transformation passes feed target-language-specific pipelines, making the conversion approach more structured than a single direct rewrite. That matters for projects whose source uses the listed constructs; code depending on unsupported Clojure features may not be a suitable fit.

Kalai is self-hosted and operated through the Clojure CLI, with configurable input and output source directories. The project is open source, but there are no paid tiers described here; support is through documentation. This makes it a reasonable candidate for solo developers or small teams comfortable with a command-line tool and handling their own environment. Choose it when the target is Rust, Java, or C++ and the source stays within its supported subset. Avoid it if you need API access, managed deployment, broad language coverage, or support channels beyond documentation.

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Kalai pricing

Kalai fact sheet

Alternatives to Kalai

• BabelFlexible ECMAScript transforms with CLI, Node.js APIs, and browser compilation.9.3
• SWCAn open-source compiler with minification and bundling for JavaScript and TypeScript workflows.9.2
• Kotlin/JSA free Kotlin-to-JavaScript toolchain for browser and Node.js projects.8.8

See all Kalai alternatives →

Featured on iTechGuides

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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Last updated 7 Oct 2026 · How we research and update