Are NanoTools completely free to use?

Yes, all basic tools on NanoTools are completely free to use with no registration required. We offer premium features for power users.

Is my data secure when using NanoTools?

Your files are processed securely and are automatically deleted after processing. We do not store your files or data on our servers.

Do I need to install any software to use NanoTools?

No installation required. All tools work directly in your browser on any device - computer, tablet, or smartphone.

What file formats are supported?

We support a wide range of formats including PDF, JPG, PNG, WebP, GIF, JSON, XML, CSV, and many more depending on the tool.

API Response Validator - Validate API Responses

Validate API responses online for free. Check JSON response against schema. API testing tool.

REST API Response Validator

Validate API responses against schemas

Schema Type

API Response (JSON)

Schema (JSON)

Usage Tips

• Paste your API response and the expected JSON Schema

• Supports JSON Schema Draft 7 specification

• Validates data types, required fields, formats, and constraints

• All validation runs client-side in your browser - your data stays private

• Useful for API testing, contract validation, and debugging

Supported validations: type, required, properties, items, format (email, url, date, ipv4, etc.), minimum, maximum, minLength, maxLength, pattern, enum

What This Tool Does

Validate JSON responses against schemas
Support JSON Schema and OpenAPI formats
Detailed error and warning messages
Type and format validation
Required field checking

How to Use

1
Paste response
Enter API response JSON
2
Add schema
Provide JSON Schema or OpenAPI spec
3
Select type
Choose schema format
4
Validate
Check compliance and review results

How it works

1

Paste response

Enter API response JSON

2

Add schema

Provide JSON Schema or OpenAPI spec

3

Select type

Choose schema format

4

Validate

Check compliance and review results

Use Cases

API contract testing
Response validation in CI/CD
OpenAPI spec validation
API version compatibility checking
Integration testing

Frequently Asked Questions

What schema formats are supported?

Supports JSON Schema (Draft 7) and OpenAPI 3.0 schema definitions.

What if validation fails?

Detailed errors show which fields failed, expected vs actual types, and missing required fields.

Can it validate nested objects?

Yes, it recursively validates all nested objects and arrays according to the schema.

Is this useful for testing?

Absolutely! Use it to validate API responses in tests, ensuring contracts are maintained across versions.