How does the slug algorithm work?

The heading is lowercased, punctuation is stripped, and spaces are replaced with dashes — matching the slug GitHub generates for each heading.

Will the same anchor work on GitLab and Bitbucket?

GitLab matches GitHub's algorithm closely. Bitbucket uses a slightly different scheme that this tool can also emit if you switch the target.

What about emojis and non-ASCII characters?

Emojis are stripped and accented characters are kept as-is — mirroring GitHub's slugger behavior.

Are the headings stored anywhere?

No. Slug generation happens entirely in your browser.

GitHub-compatible slug for every heading

Generate GitHub heading anchors

Extract every heading and turn it into a GitHub-style URL fragment — perfect for building TOCs, deep links, and navigation menus.

Anchor Generator

Input

170 B

17 lines

Output

93 B

7 lines

Status

ready

live

Ratio

0.55×

out/in

input · markdown

output · anchors

#getting-started
#install-run
#troubleshooting
#api-reference
#authentication
#endpoints
#faq

Quick Start

How to extract heading anchors

Scans every # heading in your Markdown, slugifies it the GitHub way, and emits #fragment IDs ready to drop into URLs or TOC links.

01
Paste Markdown
A README or doc with #/##/### headings.
Parsing runs through marked with GFM extensions enabled — tables, task lists, strikethrough, and fenced code blocks all match GitHub’s rendering.
inputGFMmarkedCommonMarklive
input · markdownmd · GFM
```
# Title
```
loaded · GFMGFM · ready
02
Skip code
Headings inside ``` fences are ignored.
Soft-break behaviour is configurable: by default a single newline becomes a space (CommonMark), toggle on for chat-style <br> insertion.
fencesoft-breaksoptionsconfiglive
skip · options``` · live
```
code ignored
```
options applied · livelive
03
Slugify
Spaces → dashes, punctuation removed, lowercased.
The preview is scoped under a .mde class so its CSS doesn’t bleed into the rest of the page. Output HTML is whitespace-controlled for clean diffs.
slugpreviewscoped CSSrenderstable
out · renderedid · ready
```
#getting-started
```
rendered · liverendered
04
Link them
Build TOCs, deep links, or repo nav from the list.
Export covers both raw Markdown and rendered HTML; downloads stream as text/markdown or text/html via Blob + object URL.
linkclipboard.md.htmlblob
✓ · exportedtoc · done
```
✓ linked
```
shipped · ready to shipsuccess

Pro tips

Author Markdown that renders everywhere

GFM is the safe default

GitHub-Flavored Markdown is the de-facto baseline (tables, task lists, strikethrough). CommonMark is stricter but ubiquitous as a fallback.

Soft-break behaviour varies

A single newline is a space in CommonMark, a <br> in GFM. Toggle soft breaks when source matters.

Escape inside code fences

Backticks inside fenced blocks need a longer fence — three becomes four. Use ~~~ if your content has many backticks.

Anchors are slugified

GitHub lowercases, strips punctuation, and joins with hyphens. Duplicate headings get -1, -2 suffixes.

Tables need a header row

The dash row sets alignment (:---, :-:, ---:). Use Table Aligner for diff-friendly columns.

Front matter is YAML

Triple-dash blocks at the top of files are parsed by static-site generators. Use the Front-Matter Validator to catch syntax errors.

Use Cases

When to use heading anchors

Deep-link every section of any README.

README TOC

Build a Table of Contents at the top of long READMEs. Render path uses marked with GFM extensions enabled (tables, task lists, strikethrough, autolinks), so what you preview matches what GitHub publishes bit-for-bit. Soft-break behaviour is configurable for chat-style vs prose Markdown.

GFM-compliant

Issue templates

Link from issue templates to a contributing section. Pairs cleanly with the Markdown Cheatsheet for syntax you can't quite remember — callout blocks, footnotes, definition lists. Output stays diff-friendly so style-only changes don't drown out real edits in PRs.

GitHub-perfect

Docs nav

Generate side-nav fragments for static-site generators. Cross-platform safe: anchors, code fences, and tables behave identically on GitHub, GitLab, Bitbucket, and Gitea. Heading-anchor slugs follow GitHub's lowercase-and-hyphenate rules so deep links survive a docs migration.

diff-friendly

Wiki cross-links

Cross-link sections across multi-page wikis. No server roundtrip — perfect for proprietary content you can't paste into a public tool. The full marked + GFM bundle ships with the page, so it works offline once loaded.

render-stable

Bookmarks

Share a stable URL to a specific section. Front matter (YAML / TOML / JSON) passes through unchanged so static-site pipelines (Jekyll, Hugo, Astro, Eleventy) read it correctly. Pair with the Front-Matter Validator to catch syntax errors before deploy.

cross-platform

Marketing pages

Anchor links on landing pages. Output is reproducible: identical input always produces identical Markdown, so doc-generation scripts can rely on it for snapshot tests and embedded into release workflows.

SEO-friendly

FAQ

Frequently asked questions

Whose slug algorithm is this?

GitHub's — lowercase, strip punctuation, collapse spaces and dashes. Compatible with github.com READMEs and gist.

Are duplicates suffixed?

No — this lists each heading verbatim. Use the Duplicate Heading Finder to spot collisions.

Does it handle emoji?

Emoji characters are stripped during slugify, matching GitHub's behavior.

What about code fence titles?

Anything inside ``` is skipped so language-tag lines like ```js aren't treated as headings.

Where does this run?

Locally in your browser — nothing leaves your machine.

Suggest a tool

Something missing?

Tell us what you need. We ship the top requests every two weeks.

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