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Reading API responses and debugging payloads.
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JSON Formatter and Validator: Beautify, Validate and Minify
A JSON formatter takes raw, minified or messy JSON and rewrites it with consistent indentation so people can read it, while checking that the syntax is valid. This WritoryBuzz JSON formatter and validator lets you beautify, validate and minify JSON, sort keys, repair common mistakes and convert to CSV or YAML. The page states that everything runs in your browser.
Paste JSON into the input box, choose 2 spaces, 4 spaces or Tab, then click Format. If the JSON is invalid, you get an error message that points to the problem.
Format your JSON aboveQuick start
1Paste your JSON
2Pick the indent style
3Click Format / Beautify
4Click Validate
Input JSON
Formatted Output
Explore & Convert
Format valid JSON above to see the tree view.
Click Format first, then this tab converts array-of-objects JSON to CSV.
Click Format first to see YAML output.
Click Format first to extract dot-notation key paths.
adds indentation. Validate checks the syntax. Minify removes whitespace. Valid JSON uses double quotes, has no trailing commas and has no comments. Fix / Repair can correct common slips such as trailing commas, single quotes and unquoted keys. Privacy: the page states that your JSON is processed locally and never sent to a server.
What Is JSON?
JSON stands for JavaScript Object Notation. It is a text format for exchanging structured data, and the most common format for web APIs. It is defined in RFC 8259 and in the ECMA-404 standard. Although it came from JavaScript, almost every programming language can read and write it.
JSON has six value types: object, array, string, number, boolean (true or false) and null. Objects are collections of key and value pairs in curly braces. Arrays are ordered lists in square brackets.
Sample
{"name": "Asha", "age": 29, "skills": ["SEO", "writing"], "active": true, "manager": null}
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How to Use the JSON Formatter
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1STEP 1 Paste your JSON into the Input JSON panel, or click Sample to load an example.
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2STEP 2 Pick the indent style: 2 spaces, 4 spaces or Tab.
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3STEP 3 Click Format / Beautify to produce readable output in the Formatted Output panel.
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4STEP 4 Click Validate if you only want to know whether the JSON is valid.
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5STEP 5 Click Minify to strip all whitespace for production use.
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6STEP 6 Use Sort Keys to order object keys alphabetically, which helps when comparing two files.
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7STEP 7 Click Fix / Repair if the tool reports trailing commas, single quotes or unquoted keys.
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8STEP 8 Copy the result with the Copy button, or explore it in the tree view.
Formatter vs Validator vs Minifier
| Action | What it does | When to use it |
|---|---|---|
| Formatter or beautifier | Adds line breaks and indentation. Does not change data. | Reading an API response, reviewing a config file. |
| Validator | Checks that the text follows JSON syntax and reports errors. | Before sending data to an API or committing a config. |
| Minifier | Removes all unnecessary whitespace. Does not change data. | Smaller payloads and shipped config files. |
| Repair | Attempts to correct common syntax mistakes automatically. | Quickly fixing JSON copied from code or documentation. |
Citable definition
A JSON formatter, or beautifier, adds indentation and line breaks to JSON so it is readable, and usually validates the syntax at the same time. A JSON minifier does the reverse, removing whitespace without changing the data.
The Rules of Valid JSON
- Strings and keys use double quotes. Single quotes are not allowed.
- No trailing commas after the last item in an object or array.
- No comments. Neither // nor /* */ is part of the standard.
- Keys must be strings. Unquoted keys are a JavaScript convenience, not JSON.
- Allowed values: strings, numbers, true, false, null, objects and arrays. Values like undefined, NaN and Infinity are not valid.
- Numbers cannot have leading zeros, such as 007, or a trailing decimal point.
- Control characters in strings must be escaped. A raw line break inside a string is invalid, so write it as \n.
Common JSON Errors and How to Fix Them
| Error | Invalid example | Fix |
|---|---|---|
| Trailing comma | {"a": 1, "b": 2,} | Remove the last comma: {"a": 1, "b": 2} |
| Single quotes | {'key': 'value'} | Use double quotes: {"key": "value"} |
| Unquoted key | {key: "value"} | Quote the key: {"key": "value"} |
| Comment | {"a": 1 // note} | JSON has no comment syntax. Remove it. |
| Undefined value | {"a": undefined} | Use null: {"a": null} |
| Missing comma | {"a": 1 "b": 2} | Add a comma between pairs. |
| Mismatched bracket | {"a": [1, 2} | Close the array with a square bracket before the brace. |
The first three errors can be corrected by the Fix / Repair button. For the others, read the error message, find the position it names and fix it by hand. The most common cause of a confusing error is a problem on the line before the one reported.
Explore and Convert: Tree View, CSV, YAML and Key Paths
- Tree view shows the structure as collapsible nodes, which helps with deep API responses.
- Key paths list the path to each value, handy when writing code to read a field.
- CSV convert works when the root of your JSON is an array of objects. Keys become column headers and each object becomes a row, ready for Excel or Google Sheets.
- YAML convert turns JSON into YAML, which suits configuration files because it supports comments and is easy to write by hand.
JSON vs YAML vs CSV vs XML
| Format | Best for | Strength | Weakness |
|---|---|---|---|
| JSON | APIs and data exchange | Simple, universal, strict | No comments |
| YAML | Configuration files | Readable, allows comments | Whitespace sensitive |
| CSV | Flat tables for spreadsheets | Opens anywhere | Cannot represent nested data well |
| XML | Documents and older enterprise systems | Attributes, schemas | Verbose |
Who Uses a JSON Formatter
QA testers
Checking request and response bodies.
Data analysts
Converting API output to CSV for a spreadsheet.
SEO professionals
Inspecting schema markup (JSON-LD) before publishing. If you need to build that markup, use the Schema Markup Generator.
Students
Learning JSON syntax and spotting their own mistakes.
Common Mistakes
- Pasting a JavaScript object, not JSON. Unquoted keys and single quotes are valid in JavaScript but not in JSON.
- Adding comments to a config file. If you need comments, use YAML or a format such as JSONC where the tool supports it.
- Editing minified JSON by hand. Format it first, edit, then minify again.
- Assuming Fix / Repair is always right. Always check the repaired output against what you intended.
- Pasting secrets into online tools that upload data. This tool states that processing is local, but as a habit, redact real keys when you can.
Honest Limits of This Tool
- Validation checks syntax, not meaning. It will not tell you that a field name is wrong or that a value is out of range. For that, use a JSON Schema validator.
- Browser-based tools that use JavaScript to parse JSON can lose precision on integers larger than 9,007,199,254,740,991. If you work with very large IDs, keep them as strings.
- Very large files can slow or freeze a browser tab.
- Fix / Repair handles common slips only. It cannot guess missing data or repair badly broken files.
- Duplicate keys are allowed by some parsers and ambiguous in the standard, so check for them yourself.
Privacy
The page states that formatting runs in your browser using JavaScript, and that your JSON is never sent to a server, logged or stored. That makes it suitable for everyday work with API payloads. Follow your own organisation's rules for regulated or confidential data.
Comparing two payloads? Use Text Compare to see the differences. Embedding JSON in a web page? Escape it safely with the HTML Encoder and Decoder.
Frequently Asked Questions
What is a JSON formatter?
A JSON formatter adds indentation and line breaks to JSON so it is easy to read, and checks the syntax at the same time. It does not change the data.
What is the difference between a JSON formatter, validator and minifier?
A formatter makes JSON readable. A validator checks that it follows JSON syntax. A minifier removes whitespace to make it smaller. The data stays the same in all three.
Is this JSON formatter safe for sensitive data?
The page states that all processing happens in your browser and that JSON is never sent to a server, logged or stored. Still, avoid pasting real production secrets into any online tool when you can redact them.
Why is my JSON invalid?
The usual causes are a trailing comma, single quotes, unquoted keys, a comment or a missing comma. The error message shows the position, and the problem is often on the line before it.
Can JSON have comments?
No. Standard JSON has no comment syntax. Use YAML, or JSONC where a tool supports it, such as VS Code settings files.
What does JSON minification do?
Minification removes spaces and line breaks, producing the smallest text for the same data. It is useful for production API responses and shipped configuration files.
Can I convert JSON to CSV?
Yes, if the root of the JSON is an array of objects. The keys become column headers and each object becomes a row.
Can it convert JSON to YAML?
Yes. The tool has a YAML convert view, which suits configuration files that need comments.
What does the Fix / Repair button correct?
It corrects trailing commas, single quotes and unquoted keys. Check the result, because it cannot know what you meant in more serious cases. Paste your JSON and format it now.
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Format your JSON above