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JSON Diff

Visual side-by-side comparison

JSON Validator

Validate JSON before patching

JSON-RPC Tester

Build & validate JSON-RPC requests

JSON Indenter

Format & explore JSON

JSON to Schema

Validate patch target structure

API Reference

JSON standards reference

JSON Patch Generator & Tester – RFC 6902 Online Tool

Generate, validate, and apply RFC 6902 JSON Patch operations in your browser. Use Diff mode to produce a patch from two JSON documents, or Apply mode to execute an existing patch array — no uploads, no server.

All 6 operations: add, remove, replace, move, copy, test.
Diff mode: Auto-generate the minimal patch between two JSONs.
Apply mode: Execute a patch array against a document.
Validation: Inspect patch structure and path correctness.

How to Use the JSON Patch Tool

In Diff mode, paste source JSON in the left panel and target JSON in the right panel, then click Generate Patch. The minimal RFC 6902 patch array appears in the output. In Apply mode, paste a document and a patch array, then click Apply to see the patched result.

Reference guide

RFC 6902 JSON Patch Operations

add

Adds a value at the target path. Creates intermediate objects if needed.

remove

Removes the value at the target path. Fails if path does not exist.

replace

Replaces the value at an existing path. Equivalent to remove then add.

move

Moves a value from one path to another. Atomically removes then adds.

copy

Copies a value from a source path to a target path.

test

Verifies the value at a path equals a given value. Fails the patch if not.

Example Patch Array

[
  { "op": "replace", "path": "/user/name", "value": "Alice" },
  { "op": "add", "path": "/user/role", "value": "admin" },
  { "op": "remove", "path": "/user/legacy_id" }
]

When to Use JSON Patch vs. Full Object Updates

JSON Patch shines in APIs that follow REST PATCH semantics — instead of sending the entire updated resource, you send only the operations that describe the change. This reduces payload size, prevents accidental overwrites of concurrently-changed fields, and makes audit logs human-readable. The test operation enables optimistic concurrency: assert the current state before mutating it. For visual comparison without patch generation, use our JSON Diff tool.

Frequently Asked Questions

Is my data safe with this JSON tool?

Yes. This tool uses 100% client-side processing. Your JSON data never leaves your browser and is never sent to our servers, ensuring maximum privacy and security.

Does this tool work offline?

Once the page has loaded, all processing happens locally in your browser. You can disconnect from the internet and the tool will continue to work — no server connection is required to format, validate, or convert your JSON.

Is there a file size limit?

No server-side limits apply because everything runs in your browser. Practical limits depend on your device's memory, but modern browsers handle JSON files of tens of megabytes without issue.

What is JSON Patch (RFC 6902)?

JSON Patch is an IETF standard (RFC 6902) for describing changes to a JSON document as an array of operations. Each operation is an object with an 'op' (add, remove, replace, move, copy, test), a 'path' (JSON Pointer), and optionally a 'value'. Patch arrays are compact and can be applied atomically.

What is the difference between Diff mode and Apply mode?

Diff mode takes a source and target JSON document and automatically generates the minimal patch array that transforms one into the other. Apply mode takes an existing JSON document and a patch array and produces the patched output.

What operations are supported?

All six RFC 6902 operations are supported: add, remove, replace, move, copy, and test. The 'test' operation verifies a value before applying further changes — if it fails, the entire patch is rejected.

How are JSON Patch paths written?

Paths use JSON Pointer syntax (RFC 6901). The root is '/', keys are separated by '/', and array indices use numeric positions. For example, '/users/0/name' refers to the name field of the first user in an array.