JSON Diff Tool
Compare two JSON inputs to see changes and differences. Highlights additions, deletions, and modifications with clear visual indicators.
JSON Comparison
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Enter JSON objects above and click Compare to see the differences
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About JSON Diff Tool
A JSON diff tool is a specialized comparison utility that analyzes two JSON objects or arrays and highlights the differences between them with color-coded visual indicators. This tool shows additions, deletions, modifications, and structural changes in JSON data, making it easy to identify what has changed between different versions of JSON files or API responses.
Why use a JSON Diff Tool?
Using a JSON diff tool saves significant time when comparing complex nested data structures, ensures accuracy when reviewing API changes or configuration updates, and prevents errors when merging JSON data from different sources. It provides clear visual feedback for data changes, helps with debugging API responses, and facilitates better collaboration when reviewing JSON data modifications across development teams.
Who is it for?
This tool is essential for API developers comparing JSON responses between different versions, QA testers validating API changes and data integrity, DevOps engineers reviewing configuration file changes, database administrators comparing JSON data exports, and developers working with JSON-based configurations who need to identify precise differences between JSON structures quickly and accurately.
How to use the tool
Paste the original JSON data into the left input field
Paste the modified or comparison JSON data into the right input field
The comparison updates as you type; click Compare JSON Objects to re-run it
Review the list of changes, each shown by its path with additions, deletions, and modifications color-coded
Copy the results or download them as a text file
Frequently Asked Questions
How do I compare two JSON files online?
Paste the original JSON into the left input and the modified JSON into the right one. The tool compares them as you type (you can also click Compare JSON Objects) and lists each difference by its path: additions (green), deletions (red), and modifications (yellow, with old and new values). Nested objects and arrays are compared recursively. There is no file upload or URL loading — paste the text. Diffing runs entirely in your browser; your JSON never leaves the device. Useful for: API response regression testing, configuration drift detection, and reviewing data exports.
What does the diff highlight?
Three categories. (1) Added keys — present in the right side but not the left, highlighted green. (2) Removed keys — present on the left but not the right, highlighted red. (3) Changed values — same key on both sides but different values, highlighted yellow with old and new values. The tool handles nested objects and arrays recursively, so a deep change (a value 5 levels deep in a nested object) is reported with its full path. Arrays are compared by position — index 0 of one array against index 0 of the other — so there is no order-insensitive array mode. If element order doesn't matter to you, sort both arrays before pasting.
Does key order matter in the comparison?
No — for objects, the comparison is key-by-key regardless of order in the source. {a: 1, b: 2} compared to {b: 2, a: 1} shows no differences. For arrays, the comparison IS positional — [1, 2, 3] vs [3, 2, 1] shows all three positions as changed. If you want order-insensitive array comparison, sort both arrays beforehand. This is the standard JSON-diff convention because JSON specifies objects as unordered but arrays as ordered.
Can I compare JSON from URLs or files?
Not directly — the tool has two text areas and no file upload or URL loading. Open the file or fetch the URL yourself and paste the contents into each side. For comparing committed versions of a JSON file across git history, paste the output of git show into the input fields.
Is my JSON sent to a server when I diff two values?
No. Diffing runs entirely in your browser via JavaScript. Your JSON values never reach a server, never get logged. Verify in DevTools' Network tab: comparing produces zero HTTP requests. Safe for comparing sensitive API responses, configuration with secrets, or proprietary data exports.
Regression-testing an API response after a code change?
Canonical use case. Workflow: capture the API response before deploying (save as baseline.json), deploy the change, capture the response again (current.json), paste both into the tool. Changes that should be there (the new field you added) are expected. Changes that shouldn't be there (an unrelated field whose value drifted) are regressions to investigate. For ongoing automated regression detection, run a programmatic JSON comparison in your CI pipeline — this tool is for manual investigation and ad-hoc comparison.
How much JSON can I diff at once?
Browser performance is the limit. Up to ~5 MB on each side compares in under a second. Rendering the result list is the bottleneck — past ~10 MB combined, the list may be too long to scroll usefully. For very large JSON comparison, use command-line tools that produce machine-readable output you can post-process. This tool fits the common case of comparing API responses, config files, or partial dumps — typically a few KB to a few MB per side.
How is JSON diff different from text diff?
JSON diff is structure-aware. {a: 1, b: 2} and {b: 2, a: 1} are identical in JSON terms but produce a text diff (the order changed). Whitespace and indentation differences don't show up in JSON diff (they do in text diff). JSON diff handles nesting properly — a change deep in a nested object shows up at the right level, not as a giant block of removed and re-added text. Text diff is right when you care about the literal text bytes (source code, config files where comments and formatting matter); JSON diff is right when you care about the data, regardless of presentation.
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