Markdown Outline Extractor

The Markdown Outline Extractor reads a Markdown document and pulls out every heading into a flat, ranked outline — the level, the text, its line number, and a ready-to-use anchor slug. It's the fastest way to build a table of contents, review a document's structure, or check that heading levels aren't skipping around.

What it extracts

Both heading styles Markdown supports are detected:

• ATX headings — one to six # characters (# through ######), with optional trailing closing hashes (## Section ## extracts as "Section").
• Setext headings — a line of text followed immediately by a line of = (level 1) or - (level 2) underlines.

Each result row shows the level, the heading text, a GitHub-style anchor slug (lowercased, punctuation stripped, spaces turned into hyphens, duplicates numbered — the same scheme GitHub uses for its own Markdown anchors), and the line number it appears on.

How to use it

1. Paste your Markdown into the input box — the outline updates live as you type.
2. Use the copy or download button to export the outline as CSV, or copy the anchor column to hand-build a table of contents.

What gets skipped

Headings inside fenced code blocks (fenced with ``` or ~~~) are ignored, since a # inside a code sample isn't a real heading. Only genuine ATX and Setext headings in the surrounding prose are extracted.

Common uses

• Writers and documentation teams generating a table of contents for a long README or article.
• Editors checking a document doesn't skip heading levels (jumping from # straight to ###).
• Developers scripting a docs pipeline that needs anchor links for cross-references.
• SEO teams auditing a page's heading structure before publishing.

Is my document private?

Yes. All extraction happens locally in your browser — your Markdown is never uploaded to a server.

Why does a duplicate heading get a "-1" suffix?

Anchor slugs must be unique on a page, so when the same heading text appears more than once, each repeat gets a numeric suffix appended (overview, overview-1, overview-2, ...) — the same convention GitHub and most static-site generators use for Markdown-rendered pages.