A short guide to JSON Schema Validator
Find the failure before it reaches production.
Validate JSON against a schema and get actionable failing paths. Here is the practical way to prepare the input, read the output, and decide what to check next.
01
When to reach for it
Parses the instance and schema, then checks the supported type, required-property, and property rules. It is most useful when you are dealing with invalid payload or schema mismatch. Start with the smallest example that still shows the behavior.
- Look for invalid payload, schema mismatch, required property.
- Reduce the example until one observation can change the result.
02
How to prepare the input
Paste a focused example in JSON instance followed by --- then JSON Schema. Leave out unrelated noise so the result stays easy to verify.
- Use the accepted format: JSON instance followed by --- then JSON Schema.
- Keep the facts that make the behavior reproducible.
- Do not treat missing context as a reason to invent an answer.
Example input
Safe sample
{"name":"Ada","age":"36"}
---
{"type":"object","required":["name","email"],"properties":{"name":{"type":"string"},"email":{"type":"string"},"age":{"type":"integer"}}}Run this first to see the shape of the result. Then change one meaningful fact and confirm that the output changes with it.
03
How to read the result
Reports supported validation issues with paths and the constraint that failed. Read the finding beside the evidence that produced it. The result narrows the next check; it does not claim to have changed your system.
- Separate the observed fact from the suggested next check.
- Prefer the smallest reversible experiment that can confirm or reject the finding.
- Save the output when it belongs in an incident note, review, or handoff.
04
Know the boundary
A valid document can still describe the wrong contract, and an unsupported rule is not the same as a passing validation.