JSON Formatter

Format, minify, and validate JSON. For API development and debugging.

Data is never sent to the server. Everything runs locally in your browser. Safe for sensitive information.

About this tool

This tool formats, minifies, and validates JSON in one click. Three features: 1) Format with indentation for readability, 2) Minify to one line to reduce transfer size, 3) Detect and display syntax errors. Ideal for API response inspection and debugging. All processing runs in the browser—no data sent to servers.

JSON returned from an API, squeezed into one line and impossible to read… a classic developer moment. Paste it and hit Format to turn it into an easy-to-read indented format. Or hit Minify to collapse it into a single-line JSON for transfer. If there's a syntax error, the tool points out where, so missing commas and unclosed quotes are easy to spot. Everything is processed in your browser, so you can safely handle JSON containing sensitive data like API keys. To learn the object operations that JSON is based on, we also have JavaScript fundamentals exercises.

Tool interface 

 
   
 
  
 
Usage
 
     
  1. Paste JSON into the input field (API response or log copy works)
  2. Click Format for indented output—auto-copied to clipboard
  3. Click Minify for single line. Syntax errors shown in red.
    4.  
 
 
 
When to use
 
Checking API responses, editing config files, making logs readable, preparing data for transfer.
 
 
 
Examples
 
{"name":"test","items":[1,2,3]} → Format for indent, Minify for one line.
 
 
 
Tips
 
     
  • Data stays in browser. No server upload. Safe for sensitive data.
  • Ideal for pasting API responses to inspect structure.
  • Minified JSON reduces transfer size but loses readability.
    •  
 
 
 
FAQ
 
 
 
API response is one long line—how do I make it readable?
 
Paste the JSON into this tool and click Format. Indentation makes nesting visible and structure easy to inspect. Output is auto-copied so you can paste it into your editor.
 
 
When to use JSON vs YAML?
 
| Use case | Recommended | Reason |
| \| API / data exchange \| JSON \| Industry standard | fast parse \| |
| --- | --- |
| \| Config files (docker-compose) \| YAML \| Comments allowed | human-readable \| |
| CI/CD (GitHub Actions) | YAML | Indentation = structure |
This tool converts between them.
 
 
What are common JSON syntax errors?
 
Trailing comma, missing quotes on keys/strings, comments (JSON has no comments), leading zeros in numbers (e.g. 09).
 
 
What is JSON formatting?
 
Adding indentation for readability. Formatting makes nesting visible; minifying compresses to one line for smaller transfer size.
 
 
What does JSON stand for?
 
JavaScript Object Notation. Derived from JS object syntax but now a universal data format supported by many languages.
 
 
Is trailing comma an error in JSON?
 
Yes. No comma after the last element. JavaScript allows it, but JSON is strict.
 
 
Unexpected token JSON error
 
Indicates syntax error location. Check trailing comma, missing quotes on keys, duplicate or missing commas. This tool highlights the error when you format.
 
 
JSON.parse error how to fix
 
1) Remove trailing commas 2) Wrap keys in double quotes 3) Remove comments (// or /*) — JSON has no comments 4) Use this tool to format and locate the error.
 
 
How to use the JSON formatter tool?
 
Paste your JSON and click Format to add indentation, or Minify to collapse to one line. Syntax errors are detected automatically.
 
 
How do I format API responses?
 
Paste the JSON you got from an API into this tool and click Format. The structure becomes visually clear.
 
 
Why minify JSON?
 
It reduces transfer size and makes loading faster. Minifying is common in production; formatting is common during development.
 
 
Does the JSON formatter send my data?
 
No. Everything runs in your browser. Even sensitive data can be formatted safely.
 
 
How do I check JSON syntax?
 
When you format with this tool, syntax errors are detected and displayed. Handy for debugging.
 
 
Is JSON Formatter free?
 
Free to use, no sign-up required.
 
 
Is data sent to a server?
 
Input is processed locally in your browser—nothing is sent to our servers.
 
 
Supported browsers?
 
Tested on recent Chrome, Edge, Firefox, and Safari.
 
 
Offline use?
 
Core features work offline after the first load.
 
 
vs CLI or desktop apps?
 
JSON Formatter is an install-free online alternative to CLI or desktop apps.
 
 
When to use it?
 
Use it when: Checking API responses, editing config files, making logs readable, preparing data for transfer.
 
 
Usage example?
 
Example: {"name":"test","items":[1,2,3]} → Format for indent, Minify for one line.
 
 
Main features?
 
Format and minify JSON, Syntax check and error display, Sample insert and copy
 
 
How is this different from similar tools?
 
JSON Formatter runs in the browser with no install—ideal for quick checks before heavier CLI or IDE workflows.
 
 
Search keywords
 
json formatter, json pretty print, json beautifier, json validator, format json online, json formatter online, json pretty printer, prettify json
 
 
 
 
  
 
Basic workflow
 
     
  1. Paste JSON into the input field (API response or log copy works)
  2. Click Format for indented output—auto-copied to clipboard
  3. Click Minify for single line. Syntax errors shown in red.
    4.  
 
 
Practical use cases
 
     
  • Checking API responses, editing config files, making logs readable, preparing data for transfer.
  • This tool formats, minifies, and validates JSON in one click. Three features: 1) Format with indentation for readability, 2) Minify to one line to reduce transfer size, 3) Detect and display syntax errors. Ideal for API response inspection and debugging. All processing runs in the browser—no data sent to servers.
  • Data stays in browser. No server upload. Safe for sensitive data.
  • Ideal for pasting API responses to inspect structure.
  • Minified JSON reduces transfer size but loses readability.
  • Format and minify JSON
  • Syntax check and error display
    •  
 
 
 
Privacy & data handling
 
Input is processed locally in your browser—nothing is sent to our servers.
 
 
 
Things to watch out for
 
     
  • Treat JSON Formatter as a quick check — re-verify critical values in your editor or CI before shipping.
  • This tool runs locally: closing the tab clears unsaved input. Copy results you need to keep.
  • Very large pastes can freeze a tab briefly — wait for the result before closing the tab.
  • Data stays in browser. No server upload. Safe for sensitive data.
  • Ideal for pasting API responses to inspect structure.
    •  
 
 
  
Related guides
    
Tool comparisons
   
 
Related learning content
  
  
  
 
Tool set
 
 
 
JSON & Data Format Set
  
 
Encode & Convert Set