About FreeDiffChecker
FreeDiffChecker is a free, browser-based comparison tool built for developers, writers, legal professionals, and anyone who needs to understand exactly what changed between two versions of something — instantly, without installing software or creating an account.
Built and maintained by the FreeDiffChecker Team · [email protected]
Our Story
FreeDiffChecker was built by a small independent development team who kept running into the same frustration: every time we needed to compare two files, the available tools were either limited to plain text, locked behind a paywall, or required installing desktop software that was overkill for a quick check.
We wanted a single, fast web app that could handle every kind of comparison we actually ran into day-to-day — a code diff before merging a pull request, a side-by-side of two contract drafts, a pixel-level check on a redesigned UI screenshot, a cell-by-cell comparison of two exported spreadsheets. No one tool did all of that well, so we built one.
Today FreeDiffChecker supports five comparison types: text and source code (with syntax highlighting for 50+ languages), images (with pixel-level diff and six comparison views), PDF and Word documents, Excel and CSV spreadsheets, and entire folder structures via ZIP archives. Every tool runs directly in your browser — files are processed on our servers in memory and never written to permanent storage unless you explicitly choose to save or share a result.
The service is completely free to use. You only need a free account if you want to save diffs to a personal dashboard or generate shareable links. We sustain the site through advertising and plan to keep the core comparison tools free for everyone.
Who We Built This For
Developers
Review code changes before merging, compare config files between environments, diff API responses, or audit deployment packages — all without leaving the browser.
Legal & Business Teams
Track redlines across contract versions, compare policy documents, spot changes in compliance filings, and audit report revisions with a clear before-and-after view.
Writers & Editors
Compare drafts, catch unintended edits, verify that only the intended changes made it into a final document, and keep a clean record of revision history.
What We Believe In
Speed First
Comparisons happen instantly in your browser and on our servers — no waiting, no loading screens, no page refreshes. Whether you're diffing a two-line config change or a 500-page contract, results appear in seconds.
Privacy by Design
Uploaded files are processed in memory and never written to permanent storage. Saved diffs are kept only as long as you choose — delete them any time from your dashboard. We built the tool we'd want to use ourselves.
All Formats, One Place
Text, code, images, PDFs, Word documents, Excel sheets, and entire folder trees — compared in a single tool. No switching between apps, no separate subscriptions, no installs.
What You Can Compare
Text & Source Code — Paste or upload any plain text, source file, or data file and see every changed line highlighted in red (removed) and green (added). Powered by Monaco Editor — the same engine behind VS Code — with syntax highlighting for JavaScript, TypeScript, Python, Go, Rust, Java, PHP, Ruby, SQL, YAML, JSON, XML, HTML, CSS, Markdown, Shell, C/C++, and more.
Images — Upload two PNG, JPG, WEBP, GIF, BMP, or TIFF files and compare them pixel by pixel. Switch between six views: split, fade, slider, flicker, highlight overlay, and a details panel showing similarity percentage and file metadata.
PDF & Word Documents — Upload two PDF, DOCX, DOC, or TXT files. FreeDiffChecker extracts the text content from each and presents a line-by-line diff — useful for legal contract redlining, academic paper revisions, and policy document audits.
Excel & CSV Spreadsheets — Compare XLSX, XLS, CSV, or TSV files cell by cell. Changed cells are highlighted in amber, added rows in green, and removed rows in red. Multi-sheet workbooks are fully supported.
Folders & ZIP Archives — Zip two directories and upload them to see a full directory-tree diff: which files were added, removed, or modified, with expandable line-level diffs for any text file inside the archive.