Markdown Diff Tool
Compare two Markdown files online — side by side or unified
Paste or upload two Markdown drafts, instantly see added and removed lines, ignore whitespace noise, and copy a patch you can drop into any review. Runs entirely in your browser — nothing is uploaded.
+2−1=5
Unified line diff (A → B)
How to compare two Markdown files
- Paste or open the original version in the left pane (A).
- Paste or open the revised version in the right pane (B).
- Switch between Unified and Split view to match how you read changes.
- Toggle Ignore extra whitespace when only formatting differs.
- Use Copy diff to grab a patch-style snippet you can drop into a code review comment, a release note, or a chat message.
The status badges in the toolbar show how many lines were added (+), removed (−), and unchanged (=) so you can sanity check the scale of an edit before merging.
When a Markdown diff is faster than git
- Reviewing a doc edit from a non-technical teammate. Marketing, PMs, and support engineers rarely work in git. A browser-based diff lets them paste two drafts and align on changes without learning the CLI.
- Comparing exports from different platforms. Notion, Google Docs, and CMS exports often produce subtly different Markdown for the same content. A diff highlights where the export pipeline introduced noise.
- Reconciling translations. Translators usually return prose without preserving line structure. A diff makes it easy to verify that no paragraphs were dropped during translation.
- Auditing AI-generated rewrites. When you ask an LLM to polish a draft, a diff shows exactly which sentences changed so you can re-verify factual claims.
Reading the diff output
| Marker | Meaning |
|---|---|
+ | Line exists in the revised version but not in A. |
− | Line exists in the original but was removed in B. |
| (none) | Line is unchanged between the two versions. |
Lines are matched by content, not character position. Adding a paragraph between two unchanged blocks shows up as a clean insert rather than rewriting every subsequent line.
Tips for cleaner Markdown diffs
- Keep lines short. Hard-wrapped paragraphs (~80–100 chars) produce far more readable diffs than one-line-per-paragraph Markdown. Re-flowing later is cheap; diffing a giant rewritten line is painful.
- Run a formatter first. If both files have been through the Markdown formatter, spurious whitespace differences disappear and only meaningful changes remain.
- Diff small chunks. When comparing a large document, split it with the merge & split tool and diff one section at a time.
- Pair with the heading auditor. If a diff shows reordered sections, run the heading hierarchy auditor on the result to confirm the outline is still valid.
Privacy & safety
- Everything happens client-side. The diff engine, the file picker, and the clipboard copy all run inside your browser tab.
- We never upload, store, log, or train on the Markdown you paste.
- The patch you copy is plain text — no scripts, no telemetry, no hidden encoding.
Need to learn the syntax behind what you are reviewing? Visit the Markdown guide or browse the Markdown cheat sheet.
Frequently asked questions
- A Markdown diff tool compares two versions of a Markdown document and highlights what changed line by line. It is faster than reading two files side by side and works for README updates, release notes, blog drafts, and translation reviews.
- No. The comparison runs entirely in your browser using a deterministic line-diff algorithm. Nothing is uploaded, logged, or stored, which makes the tool safe for confidential drafts and internal docs.
- Unified view stacks additions and removals in one column, ideal for spotting small inline edits. Split view shows the original on the left and the revised version on the right, ideal for reviewing larger structural changes or copy edits.
- Yes. Toggle 'Ignore extra whitespace' to collapse runs of spaces and tabs before diffing. This is useful when only formatting has changed — for example after running a Markdown formatter or when comparing across editors with different indent settings.
- Click 'Open .md' above either pane to load a file from disk. The contents are read locally and never leave your browser. You can also drag-paste from VS Code, GitHub, or your CMS.
- It complements git diff for non-engineers and quick one-off compares. If both files live in a repository, git diff and your code review tool offer richer history and review workflows. This tool is best when content is still being drafted, when comparing exports, or when you need a quick visual cue without leaving the browser.