Parsing uses deterministic rules that preserve field and type boundaries.
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Data & developer
JSON Schema Backward Compatibility Checker
Compares old and new schemas for removed fields, new requirements, type narrowing, and enum narrowing. It is a contract pre-check, not a substitute for consumer tests.
✓ Free✓ No account✓ In-browser
QUICK ANSWER
What does this tool do?
Find structural changes between two JSON Schema versions that may break consumers.
APPLICATION AND DECISION GUIDE
JSON Schema Backward Compatibility Checker: method and usage
Compares old and new schemas for removed fields, new requirements, type narrowing, and enum narrowing. It is a contract pre-check, not a substitute for consumer tests.
Syntactically valid JSON containing the object, array, or fields named by the tool Confirm the shape first with a small example containing no personal data.
a parsed structure, field metrics, and explicit syntax findings
Practical steps
- Paste the old schema first and the new schema second.
- Run the structural comparison.
- Verify every finding with real fixtures and consumer tests.
field names, value types, escaping, and empty or null values compared with the source
Verify schema, encoding, and data-loss assumptions in the target system.
Suitable use cases
- API version review — Find structural changes between two JSON Schema versions that may break consumers.
- Data-contract change log — Find structural changes between two JSON Schema versions that may break consumers.
- Local pre-CI review — Find structural changes between two JSON Schema versions that may break consumers.
LEARN THE WORKFLOW
Guides for this tool
Evolving JSON Schema and OpenAPI Contracts Without Breaking Consumers
Expose breaking candidates before release with structural diffs, anonymized fixtures, and consumer tests.
Read guide →Reliable Scheduling with Cron and Unix Time
Prevent time zones, DST, field order, and second-vs-millisecond mistakes from breaking scheduled jobs.
Read guide →ABOUT THIS TOOL
Frequently asked questions
What input does JSON Schema Backward Compatibility Checker accept?+
Syntactically valid JSON containing the object, array, or fields named by the tool Paste the old schema first and the new schema second.
What does JSON Schema Backward Compatibility Checker return?+
a parsed structure, field metrics, and explicit syntax findings Parsing uses deterministic rules that preserve field and type boundaries.
How should I validate JSON Schema Backward Compatibility Checker output?+
field names, value types, escaping, and empty or null values compared with the source
Does JSON Schema Backward Compatibility Checker send or store input on a server?+
Tool input is processed in the active tab. Saving to the Workstation or transferring to another tool is a separate choice. Consider browser extensions and shared devices separately; the privacy page explains advertising and network connections.