RedPen

6.4easy start · #24of 30
in Writing Style Checkers

Well documentedyes
Runs where you workyes

Runs on Linux, Mac, Windows.

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RedPen is ranked #24 of 30 in writing style checkers on The Geeks Club. It runs on Linux, macOS, Windows.

Compared on writing style checkers

Custom style guide: Yes
Terminology management: Yes
Editor support: Markdown, Textile, AsciiDoc, Re:VIEW, reStructuredText, LaTeX, Wiki, IntelliJ IDEA, Visual Studio Code, Vim, Emacs, Atom, WordPress, Sublime Text
Rule action: warn
API access: Yes

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The record

Purpose: RedPen is a proofreading tool for writers and programmers who write technical documents or manuals that must follow a writing standard.
Natural-language checking: It automates checks on documents written in natural languages, rather than programming languages.
Languages: The maker says RedPen works with documents in languages including English, German, Japanese, and Chinese.
Document formats: It validates markup text including Markdown, Textile, AsciiDoc, reStructuredText, and LaTeX.
Customization: Users can choose validators and add them to a configuration file.
Command-line and CI: A maker blog describes running RedPen from the command line in a Travis CI workflow to check document quality.
JetBrains integration: The RedPen IntelliJ IDEA plugin adds text validation as an editor inspection and supports plain text, properties and resource bundles, Markdown, and AsciiDoc when relevant plugins are installed.
WordPress integration: The RedPen WordPress plugin validates posts while users type and can highlight errors in the editor.
REST API: The RedPen Server provides REST endpoints for validating documents with preset or user-supplied configuration.
External validation: The WordPress plugin blog says it uses a public RedPen server by default and can be configured to use the user's own RedPen Server instance.
Support: The maker's site links to a mailing list and chat room for contact and support.
Formats: The site lists Markdown, Textile, AsciiDoc, reStructuredText, and LaTeX as supported markup formats.
Platforms: The project README lists macOS, Windows, and Linux as supported platforms.
Extensions: The project supports a plugin system that lets users write extensions with JavaScript.

Where it ranks on The Geeks Club

Best Writing Style Checkers in 2026#24 of 30

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Sources

redpen.cc· checked 8 Oct 2026
blog.redpen.cc/2016/07/· checked 8 Oct 2026
blog.redpen.cc/2016/03/· checked 8 Oct 2026
blog.redpen.cc/2016/02/15/redpen-wordpress-plugin-is-n· checked 8 Oct 2026
blog.redpen.cc/2015/05/29/rest-api-for-document-valida· checked 8 Oct 2026
github.com/redpen-cc/redpen· checked 8 Oct 2026