JSON Formatter & Validator

Format, validate, and beautify JSON instantly in your browser. Free online JSON formatter with syntax highlighting, error detection, and pretty printing. No signup required.

Features

Common Use Cases

Developers use the JSON formatter daily when debugging API responses, inspecting webhook payloads, or reviewing configuration files. It is also invaluable when working with third-party APIs that return minified, hard-to-read JSON. The validator catches common mistakes like trailing commas, mismatched brackets, and single-quoted strings before they cause runtime errors in production code.

How to Use

  1. Paste your JSON string into the Input JSON text area on the left.
  2. Click Validate to check for syntax errors. Any issues are reported with the exact character position.
  3. Click Format to pretty-print your JSON with 2-space indentation, making nested structures easy to read.
  4. Click Minify to strip all whitespace and produce the smallest possible JSON string for production use.
  5. Use the Download button to save the result as a .json file, or Copy to paste it directly into your editor.

Privacy & Security

All processing for JSON Formatter & Validator runs entirely in your browser. Your data — whether text, files, or other content — is never transmitted to any server. DevToolHub has no backend that receives or stores your inputs. This means the tool works even offline once the page has loaded, and there is no risk of your data being intercepted or stored by a third party.

Frequently Asked Questions

Is my data sent to a server?

No. All processing happens entirely in your browser using JavaScript. Your JSON is never transmitted to any server, so your data stays completely private.

Why did my JSON validation fail?

The most common errors are trailing commas after the last element in an object or array, using single quotes instead of double quotes for keys and string values, or having mismatched brackets or braces.

What is the difference between Format and Minify?

Format adds indentation and newlines to make JSON human-readable. Minify removes all whitespace to produce the smallest possible string — ideal for production use or network transmission.

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