API Response Validator
FreeValidate API JSON responses against expected schemas
About API Response Validator
When an integration breaks, the question is usually whether the API returned what your code expects, and eyeballing a JSON response rarely gives a confident answer. The API Response Validator from ToolHub by Codaiman checks a response body against an expected schema so you can confirm a payload's shape matches the contract you are coding against.
Paste the JSON your API returned along with the schema it should satisfy, and the tool verifies fields, types, and structure, flagging anything missing, extra, or mistyped. It is built for debugging integrations, catching contract drift after an API update, and adding a quick check while testing endpoints, without writing throwaway validation code. The tool runs in your browser with no account, returning results instantly so response data and schemas stay private on your machine.
Common uses
- Confirming an API response matches the schema your client code expects during integration
- Detecting contract drift after a provider updates an endpoint or version
- Debugging why deserialization fails by comparing the actual payload to its expected shape
- Validating a mocked or sample response while building against an API spec
- Checking that required fields and types are present in a third-party API's output
How to use
- 1
Configure options
Set your preferences using the options panel below.
- 2
Click Generate
Click the process button to generate your result instantly.
- 3
Copy or download
Copy the result to clipboard or download it directly to your device.
Why ToolHub?
- Instant error detection
- Detailed error messages
- Standards compliant
FAQ
How does this differ from the Schema Validator?
Both check JSON against a schema. This tool is framed for API response payloads and contract testing, making it convenient when debugging integrations.
Does it flag extra fields the schema does not define?
Depending on how your schema is written, additional properties can be reported, which helps catch unexpected fields from an API.
Can I use it to test responses while developing?
Yes. Paste a sample or live response and its expected schema to verify the shape before wiring up parsing logic.
Is the response data kept private?
Yes. Validation runs in your browser, so API responses and schemas are never uploaded or stored.
Can I use API Response Validator on mobile?
Yes — ToolHub is fully responsive and works on iPhone, Android, tablets and all modern browsers. No app install needed.