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JSON Formatter

Format, validate, and beautify JSON online. Minify JSON, convert to CSV, and check syntax errors instantly.

100% private: Your data stays in the browser.

Sponsored by the AI Security Guard platform.

JSON Error
Input
Output 

                    
                

            


            

                Size: --
                Lines: --
                Keys: --
            


            
        


        

            
JSON powers tool calls, webhooks, and agent operations

            
Agents consume JSON from APIs, users, and logs every day. Hostile payloads are a real risk. Learn how to
                harden agents that access structured data with the AI Security Action Pack. Get the latest on the future
                with the weekly Agentic AI Briefing.

            
Free Action PackSign Up: Weekly Briefing

        


        

            
How to Format JSON Online

            
    
                
  1. Paste your JSON into the input field on the left
    2. 
                
  2. Choose indent (2 spaces, 4 spaces, or tab), then click Format /
                        Beautify
    3. 
                
  3. Use Key paths below the editor to find nested keys—click a path to highlight it, or
                    use Copy on that row
    4. 
                
  4. Copy the result from the output field
    5. 
            

            
The formatter automatically validates your JSON and shows errors if the syntax is invalid.


            
What is JSON?

            
JSON (JavaScript Object Notation) is a lightweight data format used for storing and
                exchanging data. It's human-readable and widely used in web APIs, configuration files, and data storage.
            

            
{
  "name": "John Doe",
  "age": 30,
  "email": "john@example.com",
  "active": true,
  "roles": ["admin", "user"]
}


            
JSON Syntax Rules

            

            
Common JSON Errors

            
Unexpected token

            
Usually means a missing comma, extra comma, or unquoted key. Check the position indicated in the error
                message.


            
Unexpected end of JSON

            
Missing closing brace } or bracket ]. Count your opening and closing brackets.
            


            
Invalid character

            
Often caused by smart quotes from word processors, or copying from PDFs. Replace curly quotes with
                straight quotes.


            
JSON to CSV Conversion

            
This tool converts arrays of objects to CSV format:

            
// Input JSON
[
  {"name": "Alice", "age": 25},
  {"name": "Bob", "age": 30}
]

// Output CSV
name,age
Alice,25
Bob,30

            
For nested objects, the values are JSON-stringified in the CSV output.


            
Format JSON in Code

            
JavaScript

            
// Parse and format
const formatted = JSON.stringify(JSON.parse(jsonString), null, 2);

// Minify
const minified = JSON.stringify(JSON.parse(jsonString));


            
Python

            
import json

# Parse and format
formatted = json.dumps(json.loads(json_string), indent=2)

# Minify
minified = json.dumps(json.loads(json_string), separators=(',', ':'))


            
Command Line (jq)

            
# Format
cat file.json | jq '.'

# Minify
cat file.json | jq -c '.'


            

                
Frequently Asked Questions

                

                    
How do I format JSON online?

                    
Paste your JSON into a formatter tool and click Format or Beautify. The tool
                        adds proper indentation and line breaks. Most formatters also validate your JSON and show errors
                        if the syntax is invalid.

                

                

                    
How do I validate JSON?

                    
Paste your JSON into a validator. Valid JSON parses without errors. Common
                        issues: missing quotes around keys, trailing commas, single quotes instead of double quotes, and
                        unescaped special characters.

                

                

                    
How do I convert JSON to CSV?

                    
For an array of objects, each object becomes a row and each key becomes a
                        column header. Use the "JSON → CSV" button above, or in code: extract headers from the first
                        object's keys, then map each object to comma-separated values.

                

                

                    
Why is my JSON invalid?

                    
Common causes: trailing commas after the last item, single quotes instead of
                        double quotes, unquoted keys, comments (JSON doesn't support them), or special characters that
                        need escaping. Check the error message for the exact position.

                

            


            
About AI Security Guard

            
The JSON Formatter is provided by AI Security Guard, the platform for securing autonomous
                AI. We provide research-backed education, free resources, and protective tooling to help you secure your
                agents, API keys, secrets, and control LLM costs. Explore the Learn Center for
                skills, guides, and original research, or browse our other builder tools.


            
For AI Agents

            
Agents with browser automation (Puppeteer, Playwright, browser-use) can interact with this tool directly.
                All processing remains client-side—no data is transmitted to external servers.

            
Security note: JSON can be formatted in-process with JSON.parse and
                JSON.stringify in most languages. Use this page when a browser UI is required or when
                directing a user to validate JSON interactively. Tool URL: https://aisecurityguard.io/tools/json-formatter