The common data language of the modern web
JSON (JavaScript Object Notation) is a human-readable, easily machine-parsed data format built on key-value pairs. It is the backbone of REST APIs, configuration files, logs, and client-server communication.
When you use this tool, your JSON data never leaves your browser. All parsing, formatting and validation happens locally via JSON.parse / JSON.stringify. You can safely inspect JSON that contains tokens, API keys, or personal data.
For API design and security, see our REST API security guide.
About the JSON Formatter
No. All processing happens in your browser. No JSON data is sent to KEYDAL servers and no logs are kept. You can verify this in the Network tab of devtools.
JSON Schema is a specification that describes the structure of a JSON document (required fields, types, constraints). It's widely used for validating API contracts. This tool only validates syntax — for semantic/schema validation you need a dedicated library such as Ajv.
Standard JSON does not allow comments, trailing commas, or single quotes. JSONC (JSON with Comments, like VS Code settings) permits comments; JSON5 is even more relaxed — single quotes, comments, trailing commas, hex numbers. This tool parses strict standard JSON.
Yes, as far as browser memory allows — in practice JSON up to a few MB works smoothly. Gigabyte-scale files require server-side streaming parsers (e.g. Node.js stream-json).
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