Text Diff Checker
🔒 Runs in your browser
You can drop a text file onto either box.
Click a colored row to select that line in its input box above.
Three levels of detail: lines, words, characters
Line mode is best for config files, code or full contracts — it shows exactly which lines were added or removed. Word mode isolates the smallest changed word inside an otherwise identical line, which is what actually matters when comparing prose or a legal clause. Character mode goes one level further, useful for spotting a single changed digit in an id, IBAN or hash.
Nothing you paste here is ever uploaded
Both texts are compared entirely in your browser using the open-source jsdiff library — pasting an internal contract, a customer list or a production config file never sends that content anywhere. Nothing is stored either: reload the page and both sides are empty again.
Frequently asked questions
What's the difference between line, word and character mode?
Line mode compares whole lines (best for config files, code or contracts), word mode isolates the smallest changed word within a line (best for prose), and character mode highlights the exact changed letters (best for short strings like ids or hashes).
Is it safe to paste a contract or a config file with sensitive data?
Yes — both texts are compared entirely in your browser; nothing is uploaded or stored anywhere, so pasting an internal contract, a customer list or a production config carries no more exposure than opening it in a local text editor.
Why does word mode sometimes highlight a whole sentence instead of one word?
When several words change together, or word boundaries shift (e.g. a hyphenated term gets split differently), the diff groups the whole affected run together — that reflects how the underlying algorithm finds the shortest edit, not a bug.
Which algorithm powers this comparison?
A longest-common-subsequence (LCS) based diff algorithm — the same family used by git diff and the Myers diff algorithm — via the open-source jsdiff library, run entirely in your browser.