Text diff checker
Compare two text blocks and see what changed.
Paste text into both boxes and click Compare. Works well for code, config files, and prose.
About this tool
Quickly see what changed between two versions of text — a config file before and after an edit, two README drafts, an old log and a new one. This tool runs a line-by-line or word-level diff in your browser and colours the result: green for added, red for removed, grey for unchanged. Options include "ignore leading/trailing whitespace" and "ignore case" for quick sanity checks. Nothing is uploaded — the diff happens on your device.
Frequently asked questions
What's the difference between line and word diff?
Line diff compares one line at a time — best for code and config files where a whole line is added or removed. Word diff works token-by-token and is better for prose, where a sentence may have only a word or two changed.
Is this the same as git diff?
Same underlying idea (longest common subsequence) but much simpler: no patch hunks, no context lines, no file headers. Good for quick ad-hoc comparisons when you don't have the two files in a git repo.
Will large files work?
It handles reasonable inputs (tens of thousands of lines) comfortably. The algorithm is O(n·m) in memory, so pasting two novels will slow it down — for that you'd want a real diff tool locally.