Direct answer
Strict RFC 8259 JSON formatting parses, validates, and beautifies hierarchical JavaScript Object Notation data trees with precise 1-based line and column syntax diagnostics.
How to use this tool
Paste or Upload Raw JSON
Enter your JSON payload into the editor or drop a .json configuration file.
Format or Minify
Click 'Beautify' to apply 2-space or 4-space indentation, or click 'Minify' to strip extraneous whitespace.
Diagnose Syntax Errors & Inspect AST
Pinpoint precise 1-based row and column locations for syntax errors, or browse structured objects in the interactive AST tree viewer.
Strict RFC 8259 JSON Formatting, Validation & Diagnostics
JSON is the standard data interchange format for modern APIs and configuration files. Strict RFC 8259 compliance guarantees maximum cross-platform interoperability across backend environments without silent syntax corruption or unexpected deserialization bugs.
- Strict Syntax Rules: Rejects non-standard features such as trailing commas, single quotes, unquoted keys, and comments.
- Exact Diagnostics: Reports precise 1-based line and column coordinates alongside an error pointer (^) when syntax errors occur.
- Zero Auto-Mutation: Never silently mutates, truncates, or auto-repairs invalid JSON payloads without user review.
Practical examples
Beautify Minified API Response
Input: Minified: {"status":"ok","code":200,"data":[{"id":1,"name":"Item A"},{"id":2,"name":"Item B"}]}
Output: Beautified with 2-space indentation and sorted object properties for readable inspection
Restructures compact payloads into clean, legible hierarchical trees.
Limitations
- Strict RFC 8259 parsers do not support JavaScript comments (// or /* */) or undefined values.
- Non-finite numbers such as NaN, Infinity, and -Infinity are invalid in standard JSON.
Frequently asked questions
Why does the validator flag trailing commas as errors?
While permissive JavaScript parsers tolerate trailing commas, the official IETF RFC 8259 specification strictly forbids commas following the final item in arrays or objects to ensure consistent cross-language deserialization.
Is my confidential JSON data uploaded to an external server?
No. All syntax parsing, indentation formatting, and tree rendering execute entirely inside your local browser memory. Your data never leaves your device.
Authoritative References & Standards
- RFC 8259: The JavaScript Object Notation (JSON) Data Interchange Format ↗ — Authoritative standard defining JSON syntax, UTF-8 requirements, and grammar.