About this tool
Create an executable patch from two JSON documents or validate and apply an imported patch without uploading payloads or accepting partial results.
- Uses fast-json-patch 3.1.1 for JSON transformations while a strict wrapper limits operations to RFC 6902 add, remove, replace, move, copy, and test and validates RFC 6901 escapes and array indexes.
- Rejects duplicate object members, unsafe integers, non-finite numbers, prototype-sensitive paths, missing parents, invalid move destinations, oversized structures, and a root remove that would leave no JSON document.
- Runs generation and application in a disposable worker, applies the complete patch to a clone, replays it independently, and enables patch, result, and versioned evidence downloads only for fresh verified output.
How to use JSON Patch
Choose Build to generate a guarded patch from source and target JSON, or choose Apply to edit or import an RFC 6902 array. Run the isolated worker, inspect every operation and pointer, then export only after clone application and independent replay verification pass.
When this tool is useful
- Preparing a portable JSON Patch for an API, configuration migration, or deterministic test fixture.
- Reviewing an imported patch before applying it to a representative JSON document.
Practical tips
- Keep test guards enabled when the patch must fail if the source has drifted.
- Use escaped RFC 6901 paths exactly: ~0 represents a tilde and ~1 represents a slash.
- Test the exported patch in the actual receiving system because transport, authorization, and server-side behavior remain outside this browser result.
Examples you can test
Load an example, compare the result with the expected output, then replace it with your own input.
Guard a configuration update
Example input
Source version 1 and target version 2 with a changed request limit
Expected output
RFC 6902 test and replace operations plus a replay-verified result
A test guard makes source drift explicit instead of overwriting an unexpected value.
Validation checklist
- Confirm source, target, and operation order match the intended transaction.
- Resolve every ignored-member warning and review path and from pointers.
- Reapply the downloaded patch in the destination implementation before release.
- Treat root removal as unsupported rather than interpreting a missing document as JSON null.