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JSON Formatter
About This Tool
JSON Formatter is a completely free online JSON tool supporting formatting, minifying, validation and comparison, helping developers tidy up and troubleshoot JSON data quickly. Everything is processed locally in your browser and nothing is uploaded, keeping your data private and secure. No registration is needed.
How to Use
- Paste data
Paste the JSON string into the input area, copying it from an API response, log or config file.
- Process
Click Format for indented, readable JSON, Minify to strip extra whitespace, or Validate to check the data.
- View result
The formatted data supports collapsing and expanding nodes and copying paths and values, so complex data is easy to navigate.
- Copy and export
Once done, copy the result or export it to a file for API debugging and documentation.
Use Cases
- API debugging: format API responses to quickly locate field structures and error messages.
- Config editing: tidy up JSON config files for servers and databases to ensure they parse correctly.
- Teaching: turn messy data into readable format for technical articles and tutorials.
Key Advantages
- Completely free
No limits on usage or data size, no registration or login required, ready to use instantly.
- Local processing
Everything runs locally in your browser, so sensitive API data never leaves your device.
- All-in-one
Formatting, minifying, validation and comparison are covered in one tool for the whole workflow.
- Instant and fast
Processing finishes in milliseconds and results appear as you paste, with no upload or waiting.
- Easy to read
Node folding, syntax highlighting and error location make even large files easy to read.
JSON Data Types
JSON supports six basic data types, summarized in the table below:
| Type | Example | Description |
|---|---|---|
| Object | {"name": "John"} | Key-value pairs wrapped in braces; keys need double quotes |
| Array | [1, 2, 3] | An ordered list of values wrapped in brackets |
| String | "hello" | Text wrapped in double quotes, supports escape characters |
| Number | 3.14 | Integer or decimal; octal and hexadecimal are not supported |
| Boolean / null | true / null | Logic values true/false and the null value |
FAQ
A JSON formatter is an online tool that turns messy JSON strings into a readable structure, while also supporting minifying, validation and comparison. It is a handy helper for development and debugging.
Paste the JSON into the input area and click Validate. If there are syntax errors, the tool points out the error location for quick fixes.
The tool processes data locally in your browser, so keeping each input under 10MB is recommended for a smooth experience. Split very large files first.
Formatting, minifying and validation finish in milliseconds locally, with results visible immediately after pasting and no server wait.
No. Everything is processed locally in your browser and data never leaves your device, so sensitive API responses and configs are safe.
No registration or login is needed. Open the page and use all features for free with no usage limits.
Yes. The page is responsive on mobile, and core features like formatting and copying work fully, handy for emergency debugging on the go.
Desktop IDE plugins are more powerful but need installation and setup. The online tool needs no install, works across devices and is ready instantly, so the two complement each other.
Yes. Click Minify to remove indentation and line breaks and get compact single-line JSON for transmission and storage.
Common causes include missing double quotes on keys, extra or missing commas, mismatched string quotes, and trailing commas. The tool shows the error location, so fix it accordingly.
Paste both documents and use the Compare feature. Added, removed and modified nodes are highlighted so differences are easy to spot.
Standard JSON does not support comments, and data containing comments is considered invalid in strict mode. Remove comments first, or use a config format that supports them.
Content last updated：2026-07-10
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