JSON Formatter

JSON formatter and validator: pretty print, beautify and validate JSON online with instant error locations. Free, private, runs in your browser, no signup.

Client-side only Nothing stored No account needed
Last verified July 2026

This tool runs locally in your browser.

Output will appear here.
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Results are estimates based on your input only; entered values and result contents are not stored by BoringToolsKit.

Your inputs and results stay in this browser. This page may send privacy-bounded aggregate interaction events described in Privacy; it does not send your entered values or result contents.

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Method & verification

How This Tool Works

Calculation Method

Parses the pasted JSON with JSON.parse, then re-serialises it at the chosen indent (0 = compact, 2 or 4 = pretty-printed) and case (keys as written, or lowercased). A parse failure returns the error and the position instead of a result.

Site methodology

No unrelated authority link is added merely to make this page look sourced. Tool-specific external sources are shown only when they directly support the method, rate, or rule.

Assumptions to Verify

  • Inputs are treated exactly as entered.
  • Verify important decisions with current authoritative information.

Privacy: The calculation runs in this browser. Shared links contain the page address only, not your inputs or results.