Overview

CoffeeScript compiles to JavaScript that runs without a CoffeeScript interpreter. Existing JavaScript libraries work from CoffeeScript, and JavaScript can use CoffeeScript libraries, making it a reasonable option for projects that need to cross that boundary without adopting a separate runtime.

CoffeeScript 2 emits modern JavaScript, including classes and arrow functions, and supports async functions and JSX syntax. That keeps the output aligned with current JavaScript, but shifts compatibility work to the project: the target runtime must support the features in use, or the output must be transpiled. JSX output always needs transpilation.

Key features

The coffee command runs scripts, compiles .coffee files to JavaScript, and opens an interactive REPL. It can also produce inline or external source maps, which help trace compiled code during debugging. The Node API compiles CoffeeScript strings and can optionally return source maps or an abstract syntax tree, giving build tools a direct integration route.

The core compiler can run in any JavaScript environment, including a browser, without Node. The CLI, by contrast, requires Node 6 or later; most supported modern JavaScript features run natively in Node 7.6 or later. Babel transpilation is built in, but requires @babel/core to be installed.

Integration resources cover Gulp, Webpack, Grunt and Broccoli, as well as editors including Atom, Emacs, Vim and Visual Studio Code. Jest support is available through jest-preset-coffeescript. These connections make CoffeeScript easier to fit into an existing JavaScript workflow, though they do not remove the need to check output compatibility.

Pricing

CoffeeScript is free and open source, with a free plan and no free trial. There are no paid tiers or published usage charges to weigh against its capabilities.

Platforms

CoffeeScript is marked for API, Linux, macOS, web and Windows. The browser-capable core compiler gives it a web use case, while the command-line tool depends on Node.js and npm installation, either globally or as a project dependency.

Who it's for

CoffeeScript suits developers who prefer its language syntax but need to stay within JavaScript libraries and environments. It is also a plausible fit for teams adding it to an existing build chain, where its CLI, compiler API, source maps and integrations can support a source-to-source workflow.

It is a weaker choice when a project cannot accommodate transpilation or runtime checks. Modules require Node 12 or later with type set to module in package.json, and JSX output always requires transpilation. Teams should account for those constraints before making CoffeeScript part of a deployment path.

Pros and cons

Pro: It compiles to ordinary JavaScript with no runtime interpreter, while preserving access in both directions to JavaScript libraries.
Pro: CLI and API options, source maps and an interactive REPL serve both direct use and build integration.
Pro: Free, open-source availability avoids subscription costs.
Con: Modern syntax is not automatically supported by every target runtime; projects must verify compatibility or transpile.
Con: JSX always adds a transpilation requirement, and the CLI requires Node.js even though the core compiler can run in a browser.

Alternatives

Code Transpilers is the broader category to browse. Consider SWC for a free, open-source Rust-based developer toolchain; Transcrypt for a free Apache 2.0-licensed option; or Babel for a free, community-funded alternative with no paid tiers or usage limits stated.

ClojureScript is another free, open-source option under the Eclipse Public License 1.0. Google Web Toolkit offers a free Apache 2.0-licensed alternative, while Kotlin/JS is a free Kotlin compiler target for JavaScript configured with the Kotlin Multiplatform Gradle plugin. Cython is free under the Apache 2.0 license. Dart pub is also a free alternative.

Verdict

Choose CoffeeScript if you want its syntax, need to work directly with JavaScript libraries, and can manage modern-output compatibility in your build or runtime. Its no-interpreter compilation and free, flexible CLI and API are the strongest reasons to use it; look elsewhere if transpilation or Node-version constraints are a poor fit for your project.

	CoffeeScript	Scala.js
Free plan	No	Yes
Free trial	No	No
Paid from	—	Free
Open source	No	No
Platforms	api, Linux, macOS, Web, Windows	api, Linux, macOS, Web, Windows
Syntax-version conversion	Yes	—
Intermediate output	Yes	Yes
CLI access	Yes	Yes
API access	Yes	Yes
Conversion mode	source-to-source	both

CoffeeScript vs Scala.js

CoffeeScript

Scala.js