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GeekFormat

JSON Diff

Compare 1
OldOriginal JSON
1{
2 "name": "GeekFormat",
3~ "description": "面向开发者的免费在线工具集",
4~ "version": "1.0.0",
5 "features": [
6 "formatting",
7 "validation",
8~ "diff"
 
9 ],
10 "author": {
11 "name": "GeekFormat",
12 "url": "https://geekformat.com"
13 },
14 "stats": {
15~ "tools": 80,
16~ "languages": 18
17 },
18~ "active": true
19}
+1~6

Free online JSON Diff tool. Compare two JSON objects side by side with highlighted added, deleted, and modified fields. Auto-formats before performing line-by-line, character-by-character comparison, with real-time stats for additions, deletions, and modifications. Provides both text and semantic views. Ideal for API integration debugging, config file version comparison, and automated test data troubleshooting.

Related

Secure String Comparison

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Base64 Diff Checker

XML Formatter

Markdown Formatter

Use Cases

  • Comparing differences between actual response data and expected Mock data during API integration
  • Comparing version changes in JSON configuration files across different environments (dev/test/production)
  • Quickly troubleshooting inconsistencies between response data and assertion baselines in automated testing
  • Comparing response structure changes between old and new versions after upgrading third-party APIs
  • Comparing changes in the same configuration or data model before and after modifications during Code Review
  • Comparing JSON responses from normal vs. abnormal requests when troubleshooting production issues
  • Verifying consistency between source and target data during data synchronization

Features

  • Deep Diff Comparison: Auto-formats first, then performs recursive line-by-line, character-by-character comparison, precisely identifying additions, deletions, and modifications
  • Visual Highlighting: Red/green/yellow three-color scheme clearly marks deletions, additions, and modifications, with synchronized left-right scrolling
  • Character-Level Highlighting: Within modified lines, specific changed characters are further highlighted for finer-grained pinpointing
  • Auto-Formatting: Uniformly beautifies both sides of JSON before comparison, automatically eliminating interference from indentation and whitespace differences
  • Text / Semantic Dual Views: Line-by-line text comparison or structural semantic comparison, switchable with one click as needed
  • Diff Statistics: Real-time bottom stats for additions/deletions/modifications, displays "Identical" when completely matching
  • Multi-Tab Comparison: Compare multiple groups of JSON simultaneously without interference
  • Share & Swap: One-click shareable link generation, one-click left/right content swap, one-click copy for either side
  • Privacy & Security: Entirely browser-local processing, zero data upload, safe for handling responses containing secrets

How to Use

  1. Paste the two JSON contents into the left and right input boxes respectively (the tool will auto-format them)
  2. Select Text View or Semantic View to view differences marked with red/green/yellow highlights
  3. Use the bottom addition/deletion/modification statistics to confirm the scale of changes
  4. One-click copy content or generate a shareable link to collaborate with others on troubleshooting

FAQ

How do I quickly find differences between two JSON files?

Paste the two JSON texts into the left and right input boxes respectively. The tool will automatically format them first, then perform a deep line-by-line, character-by-character comparison. New content is highlighted in green, deleted content in red, and modified lines display both old and new values with changed characters highlighted, helping you instantly locate data differences.

Do I need to manually format JSON before comparing?

No. The tool automatically parses and uniformly formats (2-space indent) the JSON on both sides before comparison. So even if the two JSONs have completely different indentation, spacing, and line breaks, no meaningless differences will be produced as long as the data content is consistent. This automatically eliminates interference from whitespace characters.

What's the difference between Text View and Semantic View?

Text View compares line by line after formatting, intuitively showing additions, deletions, and modifications on each line, suitable for quickly browsing overall changes. Semantic View focuses more on comparing by JSON structure and fields, helping you understand which fields have changed from a data semantics perspective. You can switch between the two views anytime with one click.

Will different array element orders be flagged as differences?

Yes. The tool compares by formatted content order, so different array element orders will be shown as differences. If you only care about content consistency regardless of order, we recommend using the "Sort Keys" feature in the JSON Formatter tool or sorting arrays before comparing, to avoid interference caused by ordering.

What specific development and testing scenarios is this tool suitable for?

Highly suitable for the following scenarios: 1) API Integration: comparing differences between actual API responses and expected Mock data; 2) Configuration Management: comparing configuration file differences across environments (dev/production); 3) Automated Testing: as a test assertion helper to quickly troubleshoot data inconsistency issues; 4) Version Upgrades: comparing response structure changes before and after third-party API upgrades.

What's the difference between JSON Diff and JSON Formatter?

JSON Formatter organizes hard-to-read JSON into an easy-to-read hierarchical structure, while JSON Diff compares differences between two JSONs. The two are often used together: this tool actually has a built-in formatting step that automatically beautifies both sides before comparison, letting you focus on the differences themselves.

Can comparison results be shared or copied?

Yes. The tool supports compressing and encoding the current left and right content into a URL to generate a shareable link. Recipients can open it to see the same comparison scenario without uploading to a server. You can also one-click copy content from either side for code review or issue tracking.

Can I compare multiple groups simultaneously?

Yes. The tool supports multi-tab comparison. You can paste different JSON pairs in different tabs for comparison; tabs operate independently without interference, making it convenient to simultaneously troubleshoot differences across multiple APIs or configurations.

Does the comparison count how many changes were made?

Yes. The bottom status bar displays real-time counts for additions, deletions, and modifications, so you can see the scale of changes at a glance. If the two JSONs are completely identical, an "Identical" message will be displayed.

Will the compared data be uploaded to a server?

No. All formatting and diff comparison runs entirely locally in your browser. Data is never uploaded to any server. It's safe even when comparing API responses containing secrets, tokens, or user privacy. Data is cleared when you close the page.

About JSON Diff

JSON Diff refers to comparing two JSON data sets to find added, deleted, and modified fields between them. In daily development, we often need to know "what exactly is different" between two JSONs: what changed in the response structure before and after an API upgrade, where configurations differ between two environments, which field deviates between actual results and expected baselines in automated testing. Manual line-by-line checking is slow and error-prone; a JSON Diff tool can automatically highlight differences.

JSON diff comparison generally follows two approaches. One is "textual diff": after formatting JSON into canonical multi-line text, perform a Git-diff-like comparison line by line, intuitively showing additions, deletions, and modifications per line. The other is "structural/semantic diff": parse JSON into a tree structure and compare values and types one by one by field path (e.g., user.address.city), unaffected by field ordering, indentation, or other formatting factors. This tool provides both Text View and Semantic View, switchable as needed.

Why format before comparing? Because the same data can have completely different formatting (single line vs. multi-line, 2-space vs. 4-space indent). If compared directly as raw text, many "false differences" caused by formatting variations would appear. This tool automatically parses and uniformly formats both sides before comparison, eliminating whitespace interference so you only see truly meaningful data changes.

Note that key order in JSON objects is semantically unimportant ({"a":1,"b":2} is equivalent to {"b":2,"a":1}), but array element order is meaningful ([1,2] is different from [2,1]). Therefore, when you only care about array content consistency regardless of order, we recommend sorting arrays or sorting keys before comparison to avoid order changes being mistakenly identified as differences.

All formatting and comparison in this tool is done locally in the browser; data is never uploaded to servers. It also supports character-level highlighting, addition/deletion/modification counting, multi-tab simultaneous comparison, and URL sharing of comparison scenarios, suitable for API integration, config comparison, test assertions, and Code Review scenarios.

JSON Diff Type Quick Reference

When comparing two JSONs, differences typically fall into the following categories. Understanding them helps you quickly determine the nature of changes.

Diff TypeMarkerDescription
Added+ GreenFields or array elements that appear in the new version but not in the old version.
Removed− RedFields or array elements that existed in the old version but were removed in the new version.
Modified~ YellowThe field still exists but its value has changed; both old and new values are shown with changed characters highlighted.
Type Change~ YellowThe type of the field value has changed, e.g., number to string, object to array; this is a type of modification.
UnchangedNormalLines that are identical on both sides, no special marking.

Recommended Preprocessing Before Comparison

To get clean, meaningful comparison results, you may want to perform the following preprocessing as appropriate to avoid false differences.

ScenarioRecommended Action
Different key ordersSort by key names before comparison (or use Semantic View to compare at the field level).
Array order doesn't matterSort arrays by content first to avoid order changes being flagged as differences.
Different indentation/whitespaceNo action needed; this tool automatically formats and standardizes layout.
Contains large integer IDsEnsure both sides transmit large integers as strings to avoid precision loss causing mismatches.
One side is invalidUse the JSON Validate/Repair tool to fix into valid JSON before comparison.

Privacy & Security

All JSON formatting and diff comparison in this tool runs entirely locally in your browser. Data is never uploaded to any server, nor recorded or cached remotely. It is safe even when comparing API responses containing secrets, tokens, or user information. Data is cleared when you close or refresh the page.

Authoritative References

Troubleshooting

Data looks the same but differences are reported

The most common cause is different array element orders, or hard-to-spot differences in strings (e.g., full-width/half-width spaces, case sensitivity, trailing spaces, \r\n vs \n line endings). Try sorting arrays or keys before comparison. This tool already auto-formats, which usually eliminates false differences caused by indentation and ordinary whitespace.

One side reports a parse error / cannot compare

This means the content on that side is not valid JSON (e.g., missing quotes, trailing commas, contains comments, unclosed brackets). Please use the JSON Validate/Repair tool first to fix it into valid JSON, then come back to compare.

Too many differences, almost every line is marked red or green

This is most likely because key order or array order is entirely different between the two data sets, causing line-by-line misalignment. We recommend standardizing the order first (sort objects by key name, sort arrays by content) before comparison, or switch to Semantic View to see truly changed fields at the field level.

Large numbers don't match (e.g., last digit of ID differs or becomes scientific notation)

JSON numbers are parsed as IEEE 754 double-precision floats. Large integers exceeding 2^53 (snowflake IDs, order numbers) lose precision, causing both sides to look the same but be parsed as different values. Large integers should be transmitted as strings, e.g., "id": "9007199254740993".

Chinese characters displayed as \uXXXX cause apparent inconsistency

When one side uses escaped notation (\u4e2d\u6587) and the other uses plain Chinese, they may appear different after formatting. The two are semantically identical but textually different, so they will be marked as differences. You can unify whether to escape on the generating side (e.g., Python's ensure_ascii=False).