JSON and API contract tools
Validate API payloads, compare JSON responses, generate JSON Patch operations, test JSONPath expressions and inspect schemas locally in your browser. Use these tools when debugging API contracts, request/response examples, schema errors or partial updates — nothing is sent to a server.
Which JSON/API tool should I use?
JSON Schema Validator
Validate JSON against a schema (Draft-07 / 2019-09 / 2020-12) or check OpenAPI-style examples. Reports each failure with its JSON Pointer path.
Validate JSON against a schema →JSON Patch & Pointer
Generate, apply or debug RFC 6902 JSON Patch operations and RFC 6901 JSON Pointer paths before sending a PATCH request.
Generate and apply JSON Patch operations →JSON Diff
Compare two JSON payloads and identify added, removed and changed fields — useful for API regression checks across environments.
Compare JSON responses →JSONPath Tester
Test JSONPath expressions against sample JSON and confirm exactly which nodes a query selects.
Test JSONPath expressions →Schema Inspector
Inspect and understand the structure of JSON or schema data — fields, types and nesting at a glance.
Inspect JSON structure →Common JSON/API contract problems
- Validate request and response payloads before sharing with teams
- Find why a JSON Schema validation failed
- Generate a patch between two JSON versions
- Debug JSON Pointer escaping issues
- Compare API responses across environments
- Validate OpenAPI example payloads
Practical guides
- RFC 6902: why the remove target location must exist
- JSON Pointer escaping: slash and tilde examples
- JSON Patch vs JSON Merge Patch
- Generate JSON Patch from two JSON files
- Apply JSON Patch online
- Validate OpenAPI schema example JSON
Related workflows
Chain these tools into a multi-step pipeline — for example, format a response, validate it against a schema, then diff it against a baseline. Build and run them from Workflows.
FAQ
Which tool should I use to validate JSON against a schema?
Use the JSON Schema Validator. Paste your JSON payload and a JSON Schema (Draft-07, 2019-09 or 2020-12) and it reports each failure with the exact JSON Pointer path, all in your browser.
Can I generate JSON Patch from two JSON files?
Yes. JSON Diff compares two documents and JSON Patch & Pointer can express the difference as an RFC 6902 add, remove and replace operation list you can apply or send as an HTTP PATCH body.
What is the difference between JSON Patch and JSON Merge Patch?
JSON Patch (RFC 6902) is an ordered list of explicit operations such as add, remove and replace. JSON Merge Patch (RFC 7386) is a partial document where null deletes a field. Patch is precise; Merge Patch is compact but cannot target array elements. See the side-by-side comparison.
Can these tools be used for API contract testing?
Yes. Validate request and response payloads against a schema, diff responses across environments to catch regressions, and validate OpenAPI example payloads before publishing the contract.
Is my JSON uploaded to a server?
No. Every tool in this cluster runs locally in your browser. Payloads are not sent to a server and are not logged.
Keep exploring
- Security and debugging tools — sanitize HAR files, verify webhooks, decode JWTs.
- Data cleanup and QA tools — compare CSVs, clean lists, build SQL filters.
- All tools — the full utility catalog.