elm-format review
A free, open-source Elm formatter with editor integrations and validation.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
elm-format is an open-source command-line formatter for Elm source code. It is designed for developers working with Elm 0.18 and Elm 0.19 projects, whether they need to format individual files, whole directories, or source passed through standard input. It can also write formatted output to a specified file and validate whether files follow the expected format without changing them. Windows, macOS, and Linux are supported, making it suitable for solo developers and teams across common desktop environments.
Its strongest fit is an Elm-centered workflow that values consistent formatting in both the command line and the editor. elm-format documents integrations for Atom, Light Table, Vim, Emacs, Visual Studio Code, Sublime Text, JetBrains IDEs, TextMate, and Prettier, including format-on-save workflows. Through its companion integration, it can format Elm code embedded in Markdown. The project also provides a Haskell library with exposed formatting and parsing modules, which adds a programmatic option for users working in that ecosystem.
The pricing model is straightforward: elm-format is free and open source, with no paid tiers described. That makes it a practical choice when Elm formatting, validation, and editor integration are the primary requirements. Its narrow scope is also the main boundary: supported language coverage is Elm, and deployment is desktop-based. Teams seeking a formatter that spans several languages, or buyers looking for a hosted product with broader service support, should consider a different category option. Elm developers who want a focused formatter and flexible command-line workflows should pick elm-format.
elm-format pros and cons
- Where it wins
- Formats Elm files, directories, and standard input
- Supports format validation and format-on-save editor workflows
- Runs on Windows, macOS, and Linux with Markdown support
- Where it doesn't
- Supports Elm only, rather than multiple programming languages
- Provides desktop deployment rather than a hosted service
- Community and documentation support may not suit buyers needing direct support
elm-format fact sheet, pricing and score →
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