JSON Formatter & Validator
A JSON formatter turns minified or messy JSON into readable, indented text. Paste your JSON into Toolvetta’s formatter, then choose Format to pretty-print it, Validate to check it for errors with the exact line and column, or Minify to remove whitespace. Your data stays in your browser.
Runs in your browser. Your files and text are not uploaded.
How to format and validate JSON
- Paste your JSON, or open a .json file.
- Choose the indentation: 2 spaces, 4 spaces or tab.
- Select Format to beautify, Validate to check, or Minify to compress.
- Copy the result or download it as a file. To switch key names between camelCase and snake_case, use the Case Converter.
JSON Formatter & Validator: frequently asked questions
How do I format JSON online?
Paste the JSON and select Format. The output is indented with line numbers and ready to copy or download. Choose 2 spaces, 4 spaces or tabs to match your project’s style.
How do I validate JSON and find the error?
Select Validate. If the JSON is invalid, the message names the problem and shows the line and column, such as a missing comma or an extra bracket, so you can jump straight to it.
What are the most common JSON errors?
Trailing commas after the last item, single quotes instead of double quotes, keys without quotes, and comments. JSON allows none of these, even though JavaScript does.
What is the difference between format and minify?
Format (also called beautify or pretty-print) adds indentation and line breaks for reading. Minify removes all unnecessary spaces and line breaks to make the JSON as small as possible for sending or storing.
How do I decode JSON inside a Base64 string?
Decode the string with the Base64 decoder first, then paste the result here and select Format. For a JWT, decode only the middle part, between the two dots.
Can I format a large JSON file?
Yes. Open the file or paste it in. Several megabytes work in a modern browser; very large files depend on your device’s memory.
Is it safe to paste API keys or private data into this JSON formatter?
Yes. The JSON is parsed in your browser and this page does not send it anywhere. Still, remove real passwords or tokens before you share formatted output with others.
Built and tested by Zia Ur Rehman · Updated October 2026