text diff tool
Paste two versions and see what changed. Runs in your browser, so you can diff configuration, logs or API responses containing real data without sending them anywhere.
Runs in your browser — nothing is uploadedDiffing JSON
Two JSON documents can be semantically identical and textually different: key order varies, and whitespace is meaningless. Format both sides consistently before diffing, or you get a diff of the formatting rather than the data.
Invisible differences
The changes hardest to spot are the ones with no visible width. CRLF against LF makes every line differ. A trailing space shows as nothing. A non-breaking space looks exactly like a space. A BOM makes only the first line differ. And NFC against NFD makes accented text differ with no visible change at all. If a diff shows everything changed, suspect line endings; if it shows one inexplicable line, suspect an invisible character.
Questions
Why does my diff show every line as changed?
Almost always line endings: one file uses CRLF and the other LF. Normalise before comparing.
Why do two identical-looking lines differ?
An invisible character. Trailing whitespace, a non-breaking space, a zero-width space, or the same accented text in two Unicode normalization forms.
Is my text uploaded?
No. The comparison runs in your browser.
How do I compare two JSON documents properly?
Format both with the same formatter first, so you are comparing data rather than key order and indentation.