JSON Formatter & Validator
Pretty print, minify and validate JSON without sending its contents to a server.
Format JSON
Your JSON is processed locally in your browser. It is not uploaded.
JSON validation and formatting
Validation parses the complete document using the browser's JSON implementation. Formatting adds consistent indentation for review; minification removes optional whitespace for transport.
Common JSON errors
JSON requires double-quoted property names and strings. It does not allow comments, trailing commas, NaN or undefined. The reported position identifies where parsing stopped.
Frequently asked questions
Is my JSON uploaded?
No. Formatting, minification and validation run locally in your browser.
What makes JSON invalid?
Common causes include trailing commas, single-quoted strings, comments, unescaped control characters and missing brackets.
Does formatting change the data?
No. Pretty printing changes whitespace only. Minification removes unnecessary whitespace while preserving values and structure.