elm-format vs Fantomas
elm-format
github.com
Fantomas
fsprojects.github.ioSide by side
| Figure | elm-format | Fantomas |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | — | Yes |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| Plans published | 1 | 1 |
| Spec score · Code Formatting Tools | 7.9 (#11) | 8.0 (#9) |
| Editor integrations | The README lists integrations for Atom, Light Table, Vim, Emacs, Visual Studio Code, Sublime Text, JetBrains IDEs, and TextMate. | The maker provides setup guides for JetBrains Rider, Visual Studio Code, and Visual Studio. |
| Install | The README documents installation with npm install -g elm-format or by downloading a release binary. | Fantomas is installed as a .NET tool, with local installation recommended so a repository can use a fixed version. |
| Purpose | elm-format formats Elm source code according to rules based on the official Elm Style Guide. | Fantomas is an opinionated formatter for F# source code that formats files based on configuration. |
| Release | The latest release page opened is version 0.8.7, released on April 11, with fixes and improvements including a Windows npm installer fix. | The GitHub releases page lists version 8.0.7, released October 5, 2026. |
Plans
In their own words
Fantomas
Fantomas formats F# source code according to configuration, using default rules based on Microsoft’s F# style guide. Settings are also available for G-Research conventions. It runs as a .NET tool, and local installation is recommended when a repository needs to keep a fixed version. The command line accepts folders or files with `.fs`, `.fsi`, `.fsx`, `.ml` or `.mli` extensions; source files are expected to parse with the F# compiler before formatting. A limited selection of options can be placed in `.editorconfig` for automatic use by the command-line tool. For continuous integration checks, `dotnet fantomas check` reports formatting drift and exits with a failure code when files need formatting. Setup guides are available for JetBrains Rider, Visual Studio Code and Visual Studio, and the official site links to an online tool for trying the formatter and its settings. Fantomas and its library are available under the Apache 2.0 license. The project is described as an fsprojects incubation project. It is free and open source, with web access listed alongside Linux, macOS and Windows.