JSON Formatter & Validator

Format, validate, convert, diff, and query JSON entirely in your browser. Nothing uploaded, nothing tracked.

Browser-based · No upload Smart error messages Syntax highlighting No signup, no ads

Nothing you paste or upload is sent to any server — parsing, formatting, and validation run only in this tab.

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Reviewed by DoItSwift Editorial. This tool uses the browser's native JSON.parse and JSON.stringify to format and validate JSON. Lenient mode preprocesses input to strip // and /* */ comments and trailing commas before parsing. Syntax highlighting and error positioning run entirely in your browser using vanilla JavaScript — no JSON content is sent to any server. Read our editorial policy, research methodology, and fact-checking standards.

Last reviewed: April 2026 · DoItSwift Editorial

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