Add {#custom-id} anchor IDs to every heading. Useful for cross-references and deep linking.
0 anchors added
Free Markdown Anchor ID Generator appends {#slug} anchor IDs to every heading in a Markdown document. Slugs follow GitHub's auto-ID conventions (lowercase, hyphenated, deduplicated). Useful for cross-references, deep linking, and table-of-contents generators that need explicit IDs.
Privacy: This tool runs entirely in your browser. Your text is never uploaded, logged, or cached. Close the tab and it's gone. Verify in DevTools → Network: zero requests fire.
Writing {#my-heading-slug} by hand for every heading in a long document is tedious and error-prone. This tool generates all of them in one pass, for free.
| Input | Output | Typical size | Speed | Login needed |
|---|---|---|---|---|
| Markdown (.md) | Markdown with anchor IDs | Up to 5 MB | < 50 ms | No |
Here's what this free tool does in detail — every feature is built to solve real problems, runs entirely in your browser, and is free forever.
Slugs are generated using GitHub's convention: heading text is lowercased, non-alphanumeric characters are stripped, spaces become hyphens, and consecutive hyphens are collapsed. The result matches what GitHub auto-generates for anchored headings, so your cross-references work on GitHub too.
To generate a full table of contents from the anchored headings, use the Free Markdown TOC Generator.
When two headings produce the same slug (e.g., two ## Getting Started sections), the tool appends a numeric suffix: {#getting-started} for the first, {#getting-started-1} for the second. This matches GitHub's deduplication behavior.
For numbering headings with hierarchical prefixes, use the Free Markdown Auto-Number Headings tool.
Add a custom prefix to every generated slug. For example, prefix doc- produces {#doc-getting-started}. Useful for namespacing anchors when multiple documents are combined into one page.
For finding and replacing existing anchor IDs across a document, use Free Markdown Find & Replace.
By default, headings that already have a {#id} attribute are skipped. Toggle Overwrite to regenerate all anchor IDs from scratch, replacing any existing custom IDs with auto-generated ones.
To shift heading levels before generating anchors, use the Free Markdown Heading Shifter.
Drop a document with headings into the input. Click Load example for a typical multi-section doc.
Pick GitHub or custom-attr style. Add a prefix if needed. Toggle overwrite to replace existing anchors.
Every heading now has a {#slug} anchor ID. Use them for cross-references, deep links, or TOC generation.
Add explicit anchor IDs to every heading for reliable cross-references across pages.
Generate anchor IDs for Hugo, Jekyll, or Astro docs that require explicit heading slugs.
Add namespaced anchors to RFC-style documents for precise section linking.
Generate consistent heading anchors before importing Markdown into Confluence or Notion.
Add deep-link anchors to every endpoint section for easy sharing.
Yes. Free forever, no account required.
A slug like {#getting-started} appended to a heading, enabling direct links via #getting-started in the URL.
They get a numeric suffix: {#getting-started}, {#getting-started-1}, etc.
Not by default. Toggle Overwrite to regenerate all anchors from scratch.
Pandoc, Hugo, Jekyll, Astro, and many static site generators. GitHub renders them in some contexts.
No. Runs 100% in your browser.