Open source project / 2026
DeadLinkFinder
A zero-dependency Markdown integrity checker for local links, images, heading anchors and external URLs.
Context
Documentation rots quietly: renamed files, moved headings and dead images accumulate until a reader hits a 404.
The problem
Broken relative links and missing #anchors slip through review because nobody clicks every link in every doc.
Approach
DeadLinkFinder verifies local links, image assets and heading anchors fully offline, with a GitHub-compatible anchor engine covering punctuation, Unicode, emojis and duplicate headings.
System architecture
Python standard library only (re, pathlib, difflib, urllib); optional external URL checks, SARIF v2.1.0 reports with line fingerprints.
Key decisions
Every broken target comes with a 'did you mean' suggestion powered by difflib — diagnosis, not just detection.
Outcome
Available on PyPI as deadlinkfinder. It reports broken local Markdown links, missing images and heading anchors, with JSON or SARIF output. External URL checks require the optional network mode.
Learnings
Documentation quality is a build-time concern; the earlier a broken link fails, the cheaper it is.