Markdown Link Checker
Scan Markdown for malformed links: empty URLs, spaces in URLs, unclosed inline links, undefined reference labels, duplicate and unused definitions.
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What is Markdown Link Checker?
Markdown Link Checker is a client-side syntax scanner for links in Markdown documents. Paste a README, wiki page, or documentation file and it reports malformed inline links and images, reference links without definitions, duplicate definitions, and other link defects with exact line numbers. Fenced code blocks and inline code are skipped automatically, and nothing is ever uploaded — the whole scan runs in your browser.
Key Benefits
- Catch broken link syntax before it ships to your docs
- Line numbers and snippets make every issue easy to locate
- Severity filters keep large documents manageable
- Works fully offline — private documents stay private
Common Use Cases
- •Polishing a README before publishing a repository
- •Reviewing documentation pull requests for link errors
- •Cleaning up old wikis with reference-style links
- •Validating generated Markdown before deployment
How to Check Markdown Links
- Paste Markdown: Paste your README, docs page, or any Markdown content into the input box.
- Review the scan: Read the issue list — each item shows the line number, severity, and the exact snippet that failed.
- Filter issues: Switch between All, Errors, and Warnings to focus on the problems that matter most.
- Copy the report: Copy or download a plain-text report and attach it to your pull request or docs review.
Key Features
- Checks inline links and image syntax with exact line numbers
- Detects empty URLs, spaces in URLs, and unclosed parentheses
- Validates reference links, duplicate definitions, and unused definitions
- Skips fenced code blocks and inline code automatically
- Filter issues by severity with live statistics
- Copy or download a plain-text report for docs review
Frequently Asked Questions
What link problems does this tool detect?
It detects inline links and images with empty URLs, destinations containing spaces, unclosed parentheses, reference links pointing to undefined labels, duplicate reference definitions, definitions with empty URLs, malformed definitions, and unclosed autolinks.
Are links inside code blocks checked?
No. Fenced code blocks and inline code spans are skipped automatically, so example code in documentation is never flagged as a broken link.
What is the difference between an error and a warning?
Errors, such as an empty URL or an undefined reference, mean the link will not render correctly. Warnings, such as spaces in a URL or an unused definition, usually still render but may cause surprises.
Does the tool check whether URLs on the internet still work?
No — it is a syntax checker that runs fully offline. It validates the structure of links in your Markdown, not the availability of remote servers.