Forge Json

Compare JSON Objects Online

Compare two JSON objects by field and path so object-level changes are easier to review than a raw text diff.

Paste your JSON → Get results instantly (no signup)

⚡ Instant resultsNo signupRuns in your browser
Try examples:

→ Compare these JSON inputs and return a report of changed, added, and removed fi...

{
"plan": "pro",
"features": {
"aiDraft": true,
"history": true,
"apiAccess": true
},
"limits": {
"documents": 100
}
}
Output✓
1{
2  "changed": [
3    {
4      "kind": "changed",
5      "path": "plan",
6      "before": "starter",
7      "after": "pro"
8    },
9    {
10      "kind": "changed",
11      "path": "features.aiDraft",
12      "before": false,
13      "after": true
14    },
15    {
16      "kind": "changed",
17      "path": "limits.documents",
18      "before": 10,
19      "after": 100
20    }
21  ],
22  "added": [
23    {
24      "kind": "added",
25      "path": "features.apiAccess",
26      "value": true
27    }
28  ],
29  "removed": [
30    {
31      "kind": "removed",
32      "path": "features.legacyExport",
33      "value": true
34    }
35  ]
36}

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Use this exact pipeline in your app, backend, or LLM workflow.

No setup needed. Works with curl, Node, Python.

Uses example data. For edited input, copy from the playground.

Read integration guide

Works with:

  • Object snapshots
  • Feature flags
  • Config objects
  • Nested field reviews

Example: input → output

Compare JSON objects

Compare JSON objects when you care about field-level changes inside two object payloads. The input might be a user record, account settings object, feature flag map, config export, or generated response object.

This page uses the same engine as the JSON diff tool, but the content focuses on object-to-object comparison rather than full files or API response workflows.

How to compare JSON objects online

Paste the original object on one side and the changed object on the other. Run the comparison and review added fields, removed keys, and modified values. The report should point to paths like limits.documents, features.auditLog, or profile.email.

If the objects are deeply nested, use Flatten JSON when path-by-path review is easier than tree review.

JSON object comparison example

If an account object changes from "plan": "starter" to "plan": "pro", that value change should be shown clearly. If the new object adds "features": { "apiAccess": true }, the report should identify the added path without making you scan the whole object.

Common use cases

  • Compare account or user objects.
  • Review feature flag maps.
  • Check config object changes.
  • Inspect generated JSON revisions.
  • Validate object transformations.

Why object-level JSON diff matters

Objects are the shape most application code consumes. A structured object diff helps you review the fields that downstream code reads, instead of reviewing braces, indentation, or unrelated surrounding text.

Related tools

Related comparisons

Read more on the blog

Advanced usage (optional)

JSON Diff / Change Report

v1.0.0
Compare
objectarray

Description

JSON Diff / Change Report

Compare two JSON inputs and output a structured report or focused diff subset. Accepts a primary input (the new JSON) and secondary input (the old JSON), then shows what changed, was added, or was removed between them.

How It Works

This utility requires two inputs — primary (the "new" version) and secondary (the "old" version). It performs a deep comparison and outputs results based on the selected mode.

Diff Modes

Report

Return a structured report with changed, added, and removed arrays. Entries include dot paths, kind, and either before/after values or the added/removed value.

Changed Only

Return the subset of the new JSON that differs from the old JSON. Modified and added fields are included; removed fields are excluded because they do not exist in the new JSON.

Added Only

Show only fields that exist in the primary input but not in the secondary. Useful for detecting new additions.

Removed Only

Show only fields that exist in the secondary input but not in the primary. Useful for detecting deletions.

Full Annotated

Show all fields with _diff_ markers indicating their status: "unchanged", "changed", "added", or "removed". Provides a complete picture of all differences.

Configuration

FieldTypeDefaultDescription
Diff Modeenumreportreport, changed-only, added-only, removed-only, or full-annotated

Use Cases

Version Comparison

  • Config changes: Compare two versions of a configuration file to see what changed
  • API responses: Diff API responses before and after a deployment
  • Schema evolution: Identify added or removed fields between schema versions

Data Validation

  • Migration verification: Compare source and target data after migration
  • Sync detection: Find out-of-sync records between two data sources
  • Audit trail: Track exactly which fields were modified in an update

Debugging

  • State inspection: Compare application state before and after an action
  • Response diffing: Compare expected vs. actual API responses
  • Regression detection: Identify unexpected changes in output data

Configuration

NameTypeDefaultDescription
Diff Modeenumreportreport: return changed, added, and removed entries with paths. changed-only: show the new JSON subset with modified and added values. added-only: show only new keys. removed-only: show only deleted keys. full-annotated: show all with _diff markers. report changed-only added-only removed-only full-annotated

Examples

AI Prompt
Compare these JSON inputs and return a report of changed, added, and removed fields.
{
"plan": "pro",
"features": {
"aiDraft": true,
"history": true,
"apiAccess": true
},
"limits": {
"documents": 100
}
}
Output✓
1{
2  "changed": [
3    {
4      "kind": "changed",
5      "path": "plan",
6      "before": "starter",
7      "after": "pro"
8    },
9    {
10      "kind": "changed",
11      "path": "features.aiDraft",
12      "before": false,
13      "after": true
14    },
15    {
16      "kind": "changed",
17      "path": "limits.documents",
18      "before": 10,
19      "after": 100
20    }
21  ],
22  "added": [
23    {
24      "kind": "added",
25      "path": "features.apiAccess",
26      "value": true
27    }
28  ],
29  "removed": [
30    {
31      "kind": "removed",
32      "path": "features.legacyExport",
33      "value": true
34    }
35  ]
36}
Config
Diff Mode
report

API Usage

POST /api/v1/utilities/compare.json-diff
Example:
curl -X POST https://your-domain.com/api/v1/utilities/compare.json-diff \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"inputs":{"primary":{"plan":"pro","features":{"aiDraft":true,"history":true,"apiAccess":true},"limits":{"documents":100}},"secondary":{"plan":"starter","features":{"aiDraft":false,"history":true,"legacyExport":true},"limits":{"documents":10}}},"config":{"mode":"report"}}'
Response
1{
2  "changed": [
3    {
4      "kind": "changed",
5      "path": "plan",
6      "before": "starter",
7      "after": "pro"
8    },
9    {
10      "kind": "changed",
11      "path": "features.aiDraft",
12      "before": false,
13      "after": true
14    },
15    {
16      "kind": "changed",
17      "path": "limits.documents",
18      "before": 10,
19      "after": 100
20    }
21  ],
22  "added": [
23    {
24      "kind": "added",
25      "path": "features.apiAccess",
26      "value": true
27    }
28  ],
29  "removed": [
30    {
31      "kind": "removed",
32      "path": "features.legacyExport",
33      "value": true
34    }
35  ]
36}