JSON Diff Checker — Compare JSON Online
Paste two JSON objects and instantly see every added key, removed field, and changed value. Syntax highlighting included. No account. No limits.
Paste text in both panels above to compare
Or to see how it works
Compare JSON API responses
When debugging API changes between environments or versions, paste the two JSON responses side by side. The diff highlights added fields, removed keys, and changed values — so you can immediately see what your API changed between calls.
Diff JSON config files
Configuration files like package.json, tsconfig.json, or app settings often drift between environments. Use the JSON diff tool to compare production and staging configs and catch discrepancies before they cause issues.
JSON syntax highlighting
Unlike plain text diff tools, DiffCheck applies JSON syntax coloring on top of the diff highlighting. Keys, strings, numbers, and booleans are color-coded, making it much easier to read complex nested JSON structures at a glance.
Character-level value diffs
When a JSON value changes — say a URL updates or a version bumps — DiffCheck highlights the exact characters that changed within the value, not just the whole line. Spot a single digit change in a version string or a path segment change in a URL instantly.
Privacy-first — runs in your browser
JSON payloads often contain sensitive data: API tokens, user records, database IDs. DiffCheck never sends your JSON to any server. All comparison logic runs locally in JavaScript — safe for production data, credentials, and private records.
Side-by-side and inline views
Toggle between side-by-side view (both JSON documents in parallel columns) and inline view (changes interleaved with + and − prefixes). Side-by-side is ideal for reviewing large JSON objects; inline works better for a quick change summary.
How to compare JSON online
- 1
Paste your original JSON
Put the first JSON document in the left editor — this is your baseline. Works with any valid JSON: objects, arrays, nested structures.
- 2
Paste your modified JSON
Put the second JSON document in the right editor. This is what you're comparing against the original.
- 3
Read the diff
Green lines were added; red lines were removed. Within changed lines, the exact characters that differ are highlighted more intensely. JSON is selected by default for syntax coloring.
- 4
Switch views as needed
Use side-by-side to review both JSON documents in parallel, or switch to inline view for a compact change summary. Use the statistics bar to see total lines added, removed, and unchanged.
Frequently asked questions
What is a JSON diff checker?
A JSON diff checker compares two JSON documents and highlights the differences — added keys, removed keys, and changed values. It makes it easy to spot changes between API responses, config files, or any JSON data.
Is this JSON diff tool free?
Yes, completely free with no rate limits and no signup. All JSON comparison runs in your browser — your data never leaves your device.
Does my JSON need to be formatted before comparing?
No. The tool compares line by line, so pasting compact or minified JSON works fine. For the most readable diff, pasting pretty-printed JSON (each key on its own line) makes it easier to see exactly which fields changed.
Is my JSON data safe to paste here?
Yes. All diff computation runs locally in your browser using JavaScript. Your JSON is never sent to any server, never stored, and never logged. Safe to use with API keys, database records, or any sensitive JSON payloads.
What's the best way to compare two JSON API responses?
Paste both JSON responses into the editors, then switch the language to JSON for syntax highlighting. Use side-by-side view to see both responses simultaneously, or inline view to scan changes sequentially. Character-level highlighting shows exactly which values changed within each field.