JSON tools for formatting, validation, and API debugging
JSON is usually the first thing developers inspect when an API, webhook, queue message, or config file behaves unexpectedly. These tools keep the workflow direct: paste the payload, make it readable, validate the syntax, convert it when needed, and move to the next debugging step.
Tools in this workflow
Formatters
OpenJSON Formatter
Pretty-print raw JSON, minify payloads, and inspect syntax errors with clear feedback.
Formatters
OpenJSON Validator
Check JSON syntax quickly and surface readable parse errors before you ship or debug.
Formatters
OpenJSON Beautifier / Minifier
Switch between readable JSON and compact JSON without leaving the browser.
Validators & Testers
OpenJSONPath Tester
Run JSONPath expressions against sample JSON and inspect matches in a structured result panel.
Validators & Testers
OpenJSON Schema Generator
Generate a draft JSON Schema from a sample API payload for contracts, tests, and documentation.
Converters
OpenYAML to JSON
Convert YAML into readable JSON for APIs, config migrations, and test fixtures.
Converters
OpenJSON to YAML
Convert JSON into YAML for config files, docs, and human-readable environment data.
Converters
OpenJSON to Java Class
Generate POJO-style Java classes from JSON with nested object and array type inference.
Dev Debug Helpers
OpenMock Payload Generator
Generate sample JSON payloads from simple field rules or ready-made developer templates.
Related guides
Common JSON syntax errors and how to fix them
A practical guide to the JSON mistakes developers see most often: trailing commas, single quotes, comments, unescaped characters, and broken nesting.
YAML to JSON: Preserve Strings, Booleans and Leading Zeros
Convert YAML configuration to JSON without losing string IDs, leading zeros or null values. Test types, duplicate keys and a data-only round trip with a reproducible fixture.
Decode Double-Encoded JSON in an API Response
Identify a JSON object wrapped inside a JSON string, decode it in two steps, and fix the serializer that produced escaped quotes.
Debug API JSON Responses: HTML Errors, Empty Bodies and Wrong Types
Debug JSON parsing failures with repeatable examples for HTML error responses, 204 empty bodies, string-versus-object payloads and valid JSON that violates an API contract.
FAQ
Which JSON tool should I start with?
Use JSON Formatter when the payload is valid but hard to read. Use JSON Validator when you need clear syntax feedback before sharing or reusing the data.
Can these tools help with API JSON responses?
Yes. Format the response first, validate it if parsing fails, then use related tools such as JSONPath Tester or YAML conversion when the next debugging step needs it.