About DiffLab
DiffLab is a free, browser-based comparison tool for text, lists, and JSON. It is built for developers, writers, data analysts, and anyone who needs to quickly find differences between two pieces of content — without uploading files to a server or creating an account.
What you can do
- Text Compare: Compare two blocks of text by line, word, or character. Drag and drop .txt, .docx, .xlsx, and .pdf files.
- List Compare: Compare two lists and instantly see items only in A, only in B, the intersection, the union, and the symmetric difference. Paste from Excel/Sheets or drop a CSV/TSV file.
- JSON Compare: Compare two JSON objects with a collapsible tree view or a line-by-line text view. Highlights added, removed, and modified fields.
Why we built it
Most online comparison tools require you to upload your files to their server. That is a problem when your content is sensitive — source code, API responses, customer data, or internal documents. DiffLab solves this by doing everything in your browser. Your pasted text and JSON are processed locally. For file formats like .docx, .xlsx, and .pdf, the parsing libraries are loaded from a CDN, but the actual file content is never sent to any server. See our Privacy Policy for the full explanation.
Principles
- Private by design: No backend server processes your input. No accounts, no cookies, no tracking.
- Free and ad-free: No cost, no sign-up, no advertising.
- Open source: The code is on GitHub. Contributions and issue reports are welcome.
- Honest about limitations: DiffLab is a browser tool. It is not a Git client or a folder-diff tool. It does not sync files or run scheduled comparisons.