JSON Formatter

What Is a JSON Formatter?

A JSON formatter takes raw, minified, or messy JSON data and reformats it into a clean, indented structure that is easy to read and debug. JSON (JavaScript Object Notation) is the most widely used data interchange format on the web, powering REST APIs, configuration files, NoSQL databases, and more. When JSON is minified for transmission, it becomes a single unbroken line — impossible to read without formatting.

Why Use PDFJolt's JSON Formatter?

Privacy-first processing. Unlike online JSON formatters that send your data to a server, PDFJolt processes everything directly in your browser using JavaScript. Your API responses, configuration files, and sensitive data never leave your device. This matters when you're working with authentication tokens, database records, or proprietary API payloads.

Key Features

• Instant formatting — Paste JSON and get pretty-printed output with 2-space indentation
• JSON validation — Immediately identifies syntax errors with exact line and column numbers
• Minification — Compress formatted JSON into a single line for production use
• Syntax highlighting — Color-coded keys, strings, numbers, booleans, and null values
• File upload support — Drop a .json file directly into the editor
• One-click copy — Copy formatted or minified output to your clipboard
• JSON statistics — See key count, value count, nesting depth, and data size

Common Use Cases

Debugging API Responses

When working with REST APIs, responses are typically minified. Paste the raw response into PDFJolt's JSON formatter to instantly see the structure, identify missing fields, and verify data types. The syntax highlighting makes it easy to spot strings vs. numbers vs. booleans at a glance.

Validating Configuration Files

JSON configuration files (package.json, tsconfig.json, .eslintrc.json) are strict about syntax — a single trailing comma or missing quote breaks everything. PDFJolt's validator pinpoints the exact line and column of the error, saving you from hunting through hundreds of lines manually.

Minifying JSON for Production

When embedding JSON in HTML, storing it in databases, or sending it over the wire, every byte counts. The minify feature strips all whitespace and newlines, reducing file size by 30-60% depending on the original formatting.

Comparing JSON Structures

Format two JSON documents with identical indentation, then use your editor's diff tool to compare them. Consistent formatting eliminates false positives from whitespace differences.

JSON Formatter vs. Competitors

Feature	PDFJolt	jsonformatter.org	jsonlint.com	codebeautify.org
Client-side processing	Yes	No (server)	No (server)	No (server)
Syntax highlighting	Yes	Yes	No	Yes
Error line detection	Yes	Yes	Yes	Limited
File upload	Yes	Yes	No	Yes
No ads	Yes	No	No	No
Privacy	100% local	Server-side	Server-side	Server-side

Supported JSON Standards

PDFJolt's JSON formatter supports the full ECMA-404 / RFC 8259 JSON specification, including Unicode escape sequences, nested objects and arrays, scientific notation numbers, and all standard escape characters. It correctly handles edge cases like empty objects {}, empty arrays [], and deeply nested structures.

Tips for Working with JSON

• Always validate before deploying — A single syntax error can crash your application. Paste your JSON here before committing.
• Use 2-space indentation — It's the industry standard for JSON and keeps files compact while readable.
• Watch for trailing commas — Unlike JavaScript, JSON does not allow trailing commas after the last item in an array or object.
• Quote all keys — JSON requires double-quoted keys. Single quotes or unquoted keys are invalid.
• No comments allowed — Standard JSON does not support comments. Use JSONC or JSON5 if you need comments.