Markdown Formatter

A Markdown Formatter normalizes Markdown source so headings, lists, blank lines, blockquotes, tables, code fences, and common spacing follow a consistent style. It improves readability and diff reviews without converting the document to HTML.

Paste Markdown into the source panel or open a local .md file. Choose heading style, bullet marker, ordered-list numbering, code-fence style, table alignment, and trailing-space options, then click Format Markdown or enable Live mode. Review the formatted output and sanitized preview before copying or downloading.

Yes. The formatter normalizes README headings, lists, tables, code fences, blockquotes, and blank lines before you commit. Review GitHub-specific extensions such as task lists, alerts, mermaid diagrams, and HTML blocks after formatting because dialect support varies across renderers.

Yes. Fenced code content is never touched by prose whitespace normalization. The opening fence marker and optional language label are normalized to your selected fence style (backticks or tildes), but every line inside the fence remains exactly as you wrote it.

Yes. ATX headings use hash prefixes such as # Heading. Setext formatting uses underline characters for H1 (=) and H2 (-). Other heading levels always use ATX because Setext only supports two levels.

Yes. Unordered list markers can be normalized to hyphens, asterisks, or plus signs across the entire document. Nested list indentation is preserved. Review mixed-list structures in the preview before copying.

The formatter can emit sequential numbers (1. 2. 3.) or use repeated 1. lazy markers. Repeated 1. markers are valid in CommonMark and GitHub Flavored Markdown and let the renderer control numbering display.

Yes. Pipe tables with a separator row are aligned by column width or compacted to minimal spacing. The formatter reports table count and warns when a data row has a different cell count from the header row.

Yes. The preview renderer renders GFM task list items — - [ ] and - [x] — as disabled checkboxes so you can visually inspect the checklist structure. The formatter preserves task list source as-is and does not rewrite checkbox syntax.

Yes. The preview renderer converts ~~strikethrough~~ to a del element with a line-through style. The source Markdown is preserved unchanged because strikethrough is a GFM extension rather than a formatting normalization target.

Yes. The default option removes trailing spaces from line ends throughout the document. If your Markdown uses two trailing spaces for a hard line break, disable the trailing-space option or review those lines before formatting.

Yes. Consecutive blockquote lines are normalized to a consistent > prefix. Common thematic-break variants (---, ***, ___) are normalized to --- outside protected code fences and inline-code spans.

No. The preview is rendered locally from a limited Markdown renderer that escapes source text before building HTML. It does not execute scripts, inject arbitrary HTML from the document, or make any network requests.

No. It provides focused diagnostics such as unclosed fenced code blocks and uneven table row cell counts, but it is not a complete markdownlint engine and should not be described as comprehensive standards validation.

No. Its primary output is normalized Markdown source. The formatted output is still Markdown, not HTML. Use the Markdown to HTML tool when you need generated HTML, and use Markdown Preview when you primarily want rendered visual inspection.

Yes. Paste text or open a local .md, .markdown, .mdown, or .mkdn file and process it entirely in the browser. The dedicated client does not use fetch, XMLHttpRequest, beacons, localStorage, or sessionStorage for the conversion workflow.

Session history stores the last 8 formatted documents in browser memory for the current page session. You can click any history entry to reload that source into the input panel. No history is written to localStorage or any persistent storage.

Live mode applies formatting automatically 280 ms after you stop typing. It is useful for continuous editing. Disable Live mode when working with large documents to avoid reprocessing on every keystroke.

Yes. Copy Markdown sends the formatted source to the clipboard using the browser Clipboard API. Download .md saves a local formatted.md file using a Blob URL without any server upload.

It supports many common Markdown structures including ATX and Setext headings, unordered and ordered lists, blockquotes, pipe tables, links, images, fenced code, task lists, and strikethrough. It does not claim complete CommonMark or GFM conformance, so test extensions such as footnotes, alerts, math blocks, and embedded HTML in your target renderer.

Formatting aims to preserve meaning while normalizing style. Dialect-specific syntax, hard breaks, nested lists, tables with complex inline content, raw HTML, and unusual escape sequences can be sensitive to normalization. Compare source and preview, keep the original file, and run your project Markdown checks before publishing.

The stats panel shows input bytes, output bytes, saved bytes, reduction percentage, heading count, list-item count, table count, code-block count, link count, and word count. These help you understand the document structure and verify that normalization behaved as expected.

The page is a free browser utility with no account required. It provides local Markdown processing, configurable formatting controls, GFM task list and strikethrough preview, diagnostics, session history, 10-stat panel, copy, and download without sending source to a remote conversion service.