Vale is a linter for prose

A command-line tool that brings code-like linting to your writing. Enforce a consistent editorial style across every doc, in any format—entirely offline.

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bash — vale

$ vale sync

SUCCESS Synced 2 package(s) to 'styles'.

$ vale docs/

docs/configure.md

3:7 suggestion Consider using 'use' instead of 'utilize'. Microsoft.Wordiness

3:44 suggestion 'are loaded' looks like passive voice. Microsoft.Passive

9:12 error Use 'Vale CLI' instead of 'Vale cli'. Docs.Terms

docs/install.md

3:40 warning Use 'select' instead of the input-specific verb 'Click'. Microsoft.UIVerbs

4:28 error Did you really mean 'existant'? Vale.Spelling

✖ 2 errors, 1 warning and 2 suggestions in 2 files.

Setting up with an agent? Open in Claude Open in ChatGPT Agent skills

Thanks to Claude for Open Source.

Sponsor spotlights

These companies support Vale's future — and put it to work in their own products today.

Mintlify

Ships Vale as a built-in CI check.

Read the story Promptless

Runs Vale on every doc its agents write.

Read the story

Read their configs

Every team here publishes something you can open — the .vale.ini they run, or the page they wrote about running it.

Browse all 90

Why Vale

Most tools see text. Vale sees a document.

A heading, a code block, a comment, and a link URL are not the same thing—and a rule that can't tell them apart is a rule you end up switching off.

Markup-aware

Parses your markup instead of guessing at it

Twelve formats, each through a real parser rather than a pattern. Rules can target headings, lists, or table cells—and code spans, URLs, and fenced blocks are skipped before a rule ever runs.

Markdown
AsciiDoc
reStructuredText
MDX
MyST
Quarto
Typst
HTML
XML
DITA
Org
QDoc

How scopes work

Installation.md

Markdown parsed before prose rules run

#Installation

You can **utilize** Vale to lint [prose](/docs)—it ignores syntax like `code` and URLs.

>A blockquote can still contain very unique product guidance.

-Install the extension before the end result ships.

Vale is availible for macOS, Windows, and Linux.

```js

const message = "This code utilizes a URL";

```

[^install]: https://example.com/docs/utilize

Checked

headings, prose, quotes, lists

Skipped

syntax, links, code, footnotes

suggestion Consider replacing 'utilize', 'very unique', and 'end result'.

error Did you really mean 'availible'?

Code-aware

Your comments are documentation too

Vale lifts comments out of nineteen languages with tree-sitter grammars, so it knows where a comment ends and a marker inside a string literal stays code. The Markdown inside a doc comment is linted as though it were its own file.

Go
Rust
Python
Ruby
C++
C
JavaScript
TypeScript
TSX
Java
Haskell
Julia
Lua
PHP
R
QML
Protobuf
YAML
CSS

Inside the grammar

person.rs

comments extracted with tree-sitter

/// Creates a person with the given name.

///

/// # Examples

///

/// ```

/// use doc::Person;

/// let person = Person::new("name");

/// ```

pub fn new(name: &str) -> Person {

// Names can utilize any script.

let raw = "// not a comment and not prose";

}

Checked

line comments, doc comments, Markdown prose

Skipped

syntax, identifiers, strings, fenced code

suggestion Consider using 'use' instead of 'utilize'.

Extensible

Rules that read grammar, not just strings

Part-of-speech patterns, cross-file relationships, readability formulas, and Tengo scripts sit alongside the token lists—twelve extension points in all. Each is a few lines of YAML in a folder you can hand around as a package.

All twelve extension points

sequence Matches grammar, not characters

extends: sequence
message: "Use 'meetup' instead of 'meet up'."
level: error
tokens:
  - upos: NOUN
    pattern: meet
  - pattern: up

Our next meet up is on Tuesday.

Let's meet up on Tuesday.

error Use 'meetup' instead of 'meet up'.

# One alert, not two: 'meet' is a noun in the first sentence and a verb in the second.

conditional One pattern requires another

extends: conditional
message: "'%s' has no definition."
level: error
scope: text
first: '\b([A-Z]{3,5})\b'
second: '(?:\b[A-Z][a-z]+ )+\(([A-Z]{3,5})\)'
exceptions:
  - API

The HTTP endpoint requires an API key.

error 'HTTP' has no definition.

# An acronym is allowed only once its expansion appears somewhere in the file.

consistency The file has a memory

extends: consistency
message: "Inconsistent spelling of '%s'."
level: error
either:
  advisor: adviser

Ask your advisor about it.

Then ask a different adviser.

error Inconsistent spelling of 'adviser'.

# Neither spelling is wrong. Using both in one file is.

metric Arithmetic over the whole file

extends: metric
message: "Grade level (%s) is above 8."
level: warning
formula: |
  (0.39 * (words / sentences)) +
  (11.8 * (syllables / words)) - 15.59
condition: "> 8"

Notwithstanding the aforementioned considerations regarding deployment, the implementation necessitates a comprehensive understanding of the underlying architecture and its associated operational characteristics, which must be evaluated in their entirety prior to the commencement of any migration activity undertaken by the platform engineering team.

warning Grade level (31.41) is above 8.

# Counted, not matched—words, sentences, and syllables across the document.

script Drop down to real code

extends: script
message: "This paragraph runs long—consider splitting it."
level: suggestion
scope: raw
script: |
  text := import("text")
  matches := []
  for line in text.split(scope, "\n") {
    if len(text.split(line, " ")) > 40 {
      i := text.index(scope, line)
      matches = append(matches, {begin: i, end: i + len(line)})
    }
  }

suggestion This paragraph runs long—consider splitting it.

# Tengo, compiled once when the rule loads and cloned per block.

Fast

One binary, nothing to install alongside it

Written in Go, with no runtime and files linted in parallel. GitLab runs 82 rules across all 2,827 pages of its documentation in under twenty seconds.

What makes it fast

2,827: pages of Markdown
82: rules applied
<20s: start to finish

Private by design

Nothing leaves your machine. No account, no upload, and no training on your writing.

Runs everywhere

macOS, Windows, and Linux. MIT-licensed and maintained in the open.

Style guides included

Microsoft, Google, Red Hat and thirteen more, each installed with one command.

Browse every style

Distribution

Where Vale is downloaded

Also ships on WinGet v3.17.1 Snap Store v3.17.1 Linux & BSD 17 repositories

Sources: GitHub, Docker Hub, PyPI, conda-forge, Homebrew, Chocolatey, winstall, Snapcraft, and Repology · 61 contributors · updated 2026-07-24

One tool, every app

More than just a command-line interface.

Vale runs where you already write—in your editor, in your notes app, and in CI before anything merges.

Apps

Wherever the prose gets written, with diagnostics as you type.

Automation

The same run, before anything merges.

Documentation platforms

Hosted docs that run Vale for you.

Learn more about our integrations

Ready to start linting?
Install now.

Get started Check out the source code