JSON Formatter

Minified JSON is written for machines. A single line containing four thousand characters is efficient over the wire and impossible to read when an API response is not what you expected and you need to find out why. The JSON Formatter re-indents that line into a readable, hierarchical structure and tells you immediately if the document is invalid.

Validation is often the more valuable half. JSON has unforgiving rules: keys must use double quotes, trailing commas are illegal, and comments are not permitted at all despite how often people try. A parser will reject the document with a terse message, whereas seeing the formatted structure usually makes the error obvious at a glance.

Developers use it constantly while debugging API responses, checking configuration files and inspecting payloads captured from browser developer tools. It also helps non-developers who have been sent a JSON export and need to read it. Processing is local, so tokens, personal data and internal identifiers in a payload stay on your machine.

How to use the JSON Formatter

1. Paste the raw or minified JSON into the input area.
2. Format it to apply indentation and reveal the structure.
3. Read any error message, which points to the position of the problem.
4. Fix issues such as trailing commas, single quotes or unescaped characters.
5. Copy the formatted output into your editor, ticket or documentation.

Examples

• A developer pastes a failing API response to find which nested field is unexpectedly null.
• A support engineer formats a customer-supplied configuration file to spot a missing closing brace.
• An analyst makes a JSON export readable before manually extracting a handful of values.

Frequently asked questions

Why is my JSON reported as invalid?

The usual culprits are trailing commas, single quotes instead of double quotes around keys or strings, comments, or unescaped quotes and backslashes inside string values.

Is the data sent anywhere?

No. Parsing and formatting happen in your browser, so nothing is transmitted or stored.

Can it minify as well as format?

Formatting for readability is the primary function. Minified output simply removes the whitespace that formatting adds.

Does it preserve key order?

Yes, the original order of keys is retained so the formatted document matches the source structure.

SwiftMultiTool — free online tools for everyone. Home · Blog · About · FAQ · Contact