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.
Thanks to Claude for Open Source.
Read their configs
Every team here publishes something you can open — the .vale.ini they run, or the page they wrote about running it.
-
The EKS User Guide walks contributors through installing Vale for live style feedback.
docs.aws.amazon.com Cloud & infrastructure -
Runs a packaged PowerShell-Docs style in their Documentarian toolkit.
microsoft/Documentarian github.com - Discord
Vale's built-in rules across the public API documentation.
.vale.ini discord/discord-api-docs -
A required check in GitLab's documentation testing pipeline.
docs.gitlab.com Developer tools -
Powers the prose linting rules in the Grafana Writers' Toolkit.
grafana.com Data & observability - NVIDIA
All NeMo Agent Toolkit documentation is checked with Vale before it merges.
docs.nvidia.com Developer tools -
Enforces style standards across the Docker product docs.
.vale.ini docker/docs -
Maintains "Vale at Red Hat", a public style package and onboarding guide.
redhat-documentation.github.io Open source -
Publishes datadog-vale and shifted docs quality left with it.
datadoghq.com Data & observability
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.
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
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
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 pointsextends: sequence
message: "Use 'meetup' instead of 'meet up'."
level: error
tokens:
- upos: NOUN
pattern: meet
- pattern: upextends: 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:
- APIextends: consistency
message: "Inconsistent spelling of '%s'."
level: error
either:
advisor: adviserextends: metric
message: "Grade level (%s) is above 8."
level: warning
formula: |
(0.39 * (words / sentences)) +
(11.8 * (syllables / words)) - 15.59
condition: "> 8"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)})
}
}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.
Distribution
Where Vale is downloaded
- GitHub Releases0 downloads · lifetime
- Docker Hub0 downloads · lifetime
- PyPI0 downloads · past 6 mo · community-maintained wrapper
- conda-forge0 downloads · lifetime
- Homebrew0 downloads · past 12 mo
- Chocolatey0 downloads · lifetime
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.
Editors
Through the language server, so diagnostics arrive as you type.
Writing apps
The same rules, away from the editor.
Automation
The same run, before anything merges.
Documentation platforms
Hosted docs that run Vale for you.