Runs locally

JSON Formatter & Validator

Format, minify, and validate API responses, configuration files, and event payloads without uploading them.

Local processingYour input stays in this browser tab.

Input

Paste or type JSON to validate

0 charactersUTF-8 · JSON

Output

Validated and transformed JSON output

Formatted output appears here.
Waiting for valid JSONCtrl/⌘ Enter formats · Shift adds minify
How to format and validate JSON
Paste JSON into the input panel, then choose Format for two-space indentation or Minify for compact output. Both actions validate the complete document first.
Valid output can be copied or downloaded as a .json file. Your input remains in component memory and is not added to the URL, browser storage, or a server request.
Common JSON errors
  • Property names and string values require double quotes, not single quotes.
  • Trailing commas after the final object property or array item are invalid.
  • Backslashes inside strings must form valid escape sequences such as \\n or \\u0041.
  • JSON supports numbers, booleans, strings, arrays, objects, and null—not comments or undefined.
What local processing means
Formatting uses the browser's built-in JSON parser. The page does not transmit, retain, or analyze the payload. As with any sensitive data, consider trusted browser extensions, clipboard history, screen recording, and device access before pasting confidential content.
What this JSON Formatter does
Use this JSON formatter, validator, beautifier, and minifier to turn minified API responses, logs, and configuration payloads into readable JSON or compact JSON. The tool validates syntax before producing output, so malformed data is not silently changed.
When developers use it
  • Debug API responses, webhook payloads, browser console output, and copied database JSON.
  • Beautify or pretty-print JSON before code review, documentation, or manual inspection.
  • Minify JSON when you need a compact payload for transport, fixtures, or embedding.
Privacy, input, and output
Formatting and validation run locally in your browser session. PayloadHarbor does not upload JSON input to an application backend.
Paste JSON into the input panel, then choose Format for two-space indentation or Minify for compact output. Valid output can be copied or downloaded as a .json file.
Validation rules and limitations
  • Input must be valid JSON, not JavaScript object syntax with comments or trailing commas; use the JSON5 Formatter for JSON5-style config files.
  • Large documents are limited by your browser memory and editor performance.