Markdown Footnote Builder

How to use

1. 1Pick Build mode to write a new document with footnotes, or Audit mode to inspect Markdown you already have.
2. 2In Build mode, write your prose at the top and add each footnote in the row list. Use a custom id (for example source or 2024) or leave it blank to let the tool number them automatically.
3. 3Click Append first marker to drop the reference marker for the first footnote into your prose, or type [^id] markers wherever you want them.
4. 4Toggle numeric or text ids, dedupe identical footnote text, and choose whether the definitions block sits at the end of the document or after the first paragraph. Copy the assembled Markdown when you are done.
5. 5In Audit mode, paste a Markdown document. The orphan, dangling, and duplicate panels flag every problem, the inventory lists each footnote with its citation count, and the Cleaned Markdown panel returns a renumbered version you can copy back into your editor.

About this tool

Markdown Footnote Builder works two ways. In Build mode, you write the prose at the top, list every footnote in an editable row list at the side, and the tool assembles a single Markdown document with [^id] reference markers in the body and a footnote definitions block at the bottom. Numeric ids ([^1], [^2]) and text ids ([^source], [^method]) are both supported, identical footnotes can collapse to a single id, and the definitions block can sit at the end of the document or right after the first paragraph (the convention used by some MkDocs themes). A one-click insert appends the first marker to your prose, and the Pandoc inline form ^[footnote text] is generated alongside for renderers that support it. In Audit mode, you paste an existing Markdown document and the tool detects every reference and every definition, then surfaces orphan definitions (defined but never referenced), dangling references (pointing at no definition), and duplicate definitions (same id defined twice). A full inventory shows each footnote and how often it is cited, and a Cleaned Markdown panel renumbers every id in document order and rewrites the definitions block at the bottom so you can copy the audited version back into your editor. The parser walks the document once and ignores anything inside fenced code blocks, inline code spans, and HTML comments, so a [^1] that lives inside a code sample is never miscounted. Useful for technical writers maintaining long-form posts, researchers citing sources in a static-site article, documentation teams moving content between GitHub READMEs, MkDocs, Hugo, Docusaurus, Jekyll, Obsidian vaults, and Substack-style platforms, and anyone who finds themselves renumbering footnotes by hand after reordering paragraphs. Everything runs in your browser. The Markdown you paste is never uploaded.

Free to use. Works in your browser. No signup, no login.