Does this validate against a schema?

Syntax only here. Use Response Schema Validator when you have JSON Schema.

Why valid JSON but server still 400?

Semantic rules—required fields, enums—are enforced by the application, not JSON.parse.

Request Body Validator

In the same workflow: Webhook Tester and API Response Analyzer.

Request Body Validator

Check if request body is valid JSON before POST/PUT/PATCH.

Request body

✓

Valid JSON

Root: object, Size: 32 bytes

Related tools

Response Schema Validator — validate JSON against schema
JSON Diff — compare two JSONs
REST Endpoint Tester — send request and see response

Why use Request Body Validator?

Invalid JSON bodies waste support cycles—servers return 400 with little detail. Paste a proposed POST/PUT body to catch syntax errors, trailing commas, and encoding issues before you ship mobile or webhook integrations.

Practical tips

Validate after templating—string interpolation often introduces quotes or commas.
Compare against Webhook Payload Viewer output to ensure logs match on-wire bytes.
Large bodies: validate chunks if you suspect truncation upstream.

Common questions

Does this validate against a schema?: Syntax only here. Use Response Schema Validator when you have JSON Schema.
Why valid JSON but server still 400?: Semantic rules—required fields, enums—are enforced by the application, not JSON.parse.

About

Check if request body is valid JSON before POST/PUT. Validate before sending. Free JSON body checker.

Related tools

Used together

Next step

After request-body-validator, continue with Webhook Tester to validate the next API or webhook layer.