JSON Formatter
Validate, beautify, and query your JSON. Includes Tree View, JMESPath filtering, and TypeScript/Go auto-generation.
What is a JSON Formatter?
A JSON (JavaScript Object Notation) Formatter is an essential developer tool used to parse, validate, and beautify minified or unreadable JSON data strings into a human-readable format. It ensures that the document syntax is strictly valid according to RFC 8259, adding appropriate indentations, line breaks, and whitespace.
How to Use This JSON Formatter
- 1 Paste your JSON: Copy your unformatted JSON payload from your API response, log file, or document and paste it into the left-hand editor pane.
- 2 Format or Minify: Click the
Formatbutton to beautify the code, orMinifyto strip out all unnecessary whitespace for production transmission. - 3 Explore with Tree View: If your JSON document is massive, click the "Tree" tab on the right side to visually drill down into nested objects and arrays without getting lost.
- 4 Generate Types: Click the "Export" tab to automatically safely generate completely typed structures like TypeScript Interfaces or Go Structs based on the actual shape of your pasted JSON.
Real-Life Developer Use Cases
Why do thousands of developers use an online JSON formatter daily?
- API Debugging: When inspecting network requests from REST or GraphQL endpoints, payloads are universally minified to save bandwidth. Formatting the data is the first step to debugging an issue.
- Configuration File Editing: Editing deeply nested
.jsonconfig files manually is error-prone. Paste it here to catch trailing commas or missing quotes instantly. - Data Filtering using JMESPath: Dealing with a 10MB JSON file containing 10,000 user records? Use our built-in JMESPath query bar to type
users[?age > 30].nameand instantly visualize only the data you need.
Privacy First: Why Client-Side Matters
Most online JSON formatters send your data to a remote server to be processed using server-side languages like PHP or Python. If you paste a production database dump containing Personally Identifiable Information (PII) or API keys, that data is instantly compromised and often logged in their server history.
The Simple Toolbox JSON Formatter runs 100% locally in your web browser. The code processing your text is running directly on your CPU using JavaScript’s native JSON.parse(). When you format data here, not a single byte is ever sent over the network. It's completely safe for sensitive enterprise data.
Frequently Asked Questions
Can this tool fix invalid JSON?
Yes, to a degree. If you click the "Repair" button in the toolbar, our tool uses heuristics to attempt to fix the most common JSON syntax errors: single quotes instead of double quotes, and rogue trailing commas at the end of objects/arrays.
What happens to my data after I format it?
Absolutely nothing. Because this tool acts purely as a client-side calculator, the data only exists in your browser's active memory tab. Once you close the tab, it's gone forever. We have no databases and no server logs for your input.
How do I generate TypeScript Interfaces from JSON?
Paste any valid JSON object array into the left panel. On the right panel, select the "Export" tab and choose "TypeScript Interface" from the dropdown. The system recursively walks through your JSON properties, deduces their native types (strings, numbers, booleans, arrays), and builds a strict TypeScript interface definition you can copy directly into your codebase.
The tools and calculators provided on The Simple Toolbox are intended for educational and informational purposes only. They do not constitute financial, legal, tax, or professional advice. While we strive to keep calculations accurate, numbers are based on user inputs and standard assumptions that may not apply to your specific situation. Always consult with a certified professional (such as a CPA, financial advisor, or attorney) before making significant financial or business decisions.
Free Tools Alert
Join 10,000+ creators. Get our newest productivity tools, templates, and calculators directly to your inbox every month.
No spam. One-click unsubscribe.