Free tool
JSON diff
Paste two JSON documents and see what changed, side by side. Formatting and key order are ignored, so only real changes show. Runs in your browser; nothing is uploaded.
Runs in your browser. Nothing you paste leaves this page.
What this compares
Both documents are parsed, then pretty-printed the same way, then compared line by line with the changed values marked inside each line. A reformatted file with no real changes shows no differences. With Ignore key order on, object keys are sorted at every level first, so {"a":1,"b":2} and{"b":2,"a":1} are the same document. Arrays keep their order, because in JSON array order is data.
Invalid JSON is reported with the parser's message rather than compared as text. Fix the trailing comma or the missing quote and the comparison runs again as you type.
JSON diffs in git
git diff knows nothing about JSON. It compares lines, so a key that moved, a file that was re-indented, or a value that changed inside a long line all look the same: red line, green line. Two ways around it. Pretty-print the files consistently before committing, so the line diff stays honest. Or review in a client that renders JSON as structure, which is what Meridian's rendered preview does for JSON, CSV, Markdown, SVG and images: the old version beside the new, as documents, for every file in the repository.
Comparing CSV instead? The CSV diff tool works the same way with cell-level marks. For the command itself, see git diff, explained.
The same view, for every file in your repo
Meridian is a native Git client for the Mac that renders JSON, CSV, Markdown and image diffs as documents, old beside new, then lets you stage and commit. No pasting.
Free 14-day trial | One licence, three Macs
Related: CSV diff | Markdown diff | git diff, explained
JSON diffs, answered
Does my JSON get uploaded anywhere?
No. The comparison runs in your browser. This page makes no network requests with your data, and there is no server to send it to.
Why does the tool reformat my JSON?
Both sides are parsed and pretty-printed with two-space indentation before comparing, so a change in whitespace or line breaks never shows up as a difference. Only the values and structure are compared.
What does "Ignore key order" do?
It sorts object keys on both sides before comparing, at every level. Two documents with the same keys and values in a different order then show no differences. Turn it off to compare the documents exactly as written.
How do I diff two JSON files in git?
git diff compares them line by line, so a reordered key or reformatted file looks fully changed. Pretty-print both versions first, or use a client that renders JSON as structure. git diff, explained covers the command.
Can I compare JSON inside a git client instead of pasting it?
Meridian renders JSON, CSV, Markdown and image diffs as documents, old version beside new, for every file in a repository, with no pasting. It is a native Mac Git client with a 14-day trial.