Readability analyzes Markdown files and reports measures of how complex their words and sentences may be. Its results include grade level, reading ease, and estimated reading time based on 200 words per minute. The listed grade-level formulas are Flesch-Kincaid, Gunning Fog, Coleman-Liau, SMOG, and ARI. It also reports word and sentence metrics and can detect or require MkDocs-style admonitions. Results can be produced as a table, Markdown, JSON, summary, or report. The tool can run as a Go command-line program, in Docker, as a GitHub Action, or from source; pre-commit hooks are documented too. Configurable thresholds can make CI checks fail when documentation exceeds them. A .readability.yml file supports path-specific overrides, and a JSON Schema is available for editor validation and autocomplete. The GitHub Action can run checks in workflows and add a formatted report to the Actions job summary. Documented CI/CD examples cover GitLab CI, CircleCI, and Jenkins. The project is MIT licensed and provides pre-built binaries for Linux and macOS in amd64 and arm64, and for Windows in amd64. Its Docker guide describes Cosign image signatures, a signed SBOM, and a distroless base image that runs as a non-root user. Readability scores assess word and sentence complexity; they do not determine accuracy, completeness, context, or tone.
Who it is for
Readability suits bloggers, technical writers, documentation teams, and students who want to review how difficult Markdown content may be to read. Its threshold checks and workflow integrations also fit teams that want automated readability checks in CI.
What is good
- Reports several grade-level scores, reading ease, and estimated reading time.
- Offers table, Markdown, JSON, summary, and report outputs.
- Thresholds can fail CI checks when documentation exceeds them.
- Runs as a CLI, Docker image, GitHub Action, or pre-commit hook.
- MIT licensed, with Linux, macOS, and Windows binaries.
What to know first
- Scores do not assess accuracy, completeness, context, or tone.
- The documented Windows binary is for amd64 only.
- Plain-language rewrites and accessibility guidance are not provided.
Verdict
Choose Readability if you want a free, open-source way to measure text complexity and enforce thresholds in documentation workflows. Look elsewhere if you need automated plain-language rewrites, accessibility guidance, or an assessment of accuracy and tone.
Get started with Readability
- Visit the Readability project website.
- Choose an installation route: Go command-line tool, Docker, GitHub Action, pre-commit hooks, or build from source.
- Download a pre-built binary for a listed operating system and architecture, if applicable.
- Set thresholds and path-specific overrides in .readability.yml.
- Run checks locally or in a CI workflow and choose an output format.
What the free plan stops at
The project lists a free MIT-licensed plan with its GitHub Action, CLI, and Docker image; no paid plans are listed. Its scores cover word and sentence complexity, not accuracy, completeness, context, or tone.
Questions about Readability
Is Readability free and open source?
Yes. The listed Readability plan costs $0.00 per free, and the project identifies its license as MIT.
What does Readability analyze?
It analyzes Markdown files and reports grade level, reading ease, estimated reading time, and word and sentence metrics. It can also detect or require MkDocs-style admonitions.
How can I run it?
Documented options include a Go command-line tool, Docker, a GitHub Action, pre-commit hooks, and building from source.
Which operating systems have pre-built binaries?
Binaries are listed for Linux and macOS in amd64 and arm64, and Windows in amd64.
Can it check documentation in CI?
Yes. Configurable thresholds can fail CI checks, and a GitHub Action can add a formatted report to the Actions job summary.
Does it rewrite text or check accessibility?
Plain-language rewrites and accessibility guidance are listed as unavailable. The project says its scores assess word and sentence complexity, not accuracy, completeness, context, or tone.
Readability plans and pricing
All plansCompared on AI readability checkers
- Grade-level analysis
- Yes
- Sentence complexity
- Yes
- Plain-language rewrites
- No
- Accessibility guidance
- No
- Input formats
- document
