JSON FORMATTER & VALIDATOR
Format, validate, and minify JSON instantly in your browser. Syntax error detection with line numbers, copy/download, and file size stats.
// ABOUT JSON
What Is JSON and Why Format It?
JSON (JavaScript Object Notation) is the standard data format for APIs and web services. APIs return JSON as a single compressed line with no whitespace — fast for transmission, unreadable for humans. Formatting adds indentation and line breaks so you can quickly scan the structure, find specific keys, and understand the shape of the data. This is the first thing to do when debugging an API response.
Format vs Minify — When to Use Each
Format (prettify) is for reading: adds indentation and line breaks, making nested objects and arrays easy to navigate. Use it when debugging, reviewing, or documenting data. Minify is for shipping: removes all whitespace to produce the smallest possible payload. Use it before embedding JSON in a web page, storing it in a database, or sending it over an API where every byte of bandwidth counts.
Common JSON Syntax Errors
The most frequent JSON mistakes: trailing commas after the last item in an array or object (valid in JS, invalid in JSON), single quotes instead of double quotes for strings and keys, unquoted keys, and comments (JSON has no comment syntax). Paste your JSON here and the validator will pinpoint exactly where the error occurs with a line number.
Your Data Never Leaves Your Browser
Unlike many online JSON tools, this formatter processes everything locally using the browser's built-inJSON.parse()andJSON.stringify(). No data is uploaded, sent to a server, or logged. Safe to use with API keys, credentials, internal config files, or any sensitive data you need to inspect.
// FAQ
FREQUENTLY ASKED QUESTIONS
Q1.Is my JSON data sent to a server?
No. All formatting and validation happens locally in your browser using JavaScript's built-in JSON.parse(). Your data never leaves your device.
Q2.What errors will the validator catch?
Any syntax error that makes JSON invalid: missing commas, unclosed brackets, trailing commas, unquoted keys, single quotes instead of double quotes, and more. The error message will show the position where parsing failed.
Q3.What's the difference between Format and Minify?
Format (prettify) adds indentation and line breaks to make JSON human-readable. Minify removes all whitespace to produce the smallest possible file size — useful for APIs and production data.
Q4.Is there a size limit?
No enforced limit, but very large JSON files (10MB+) may be slow to process depending on your browser and device.
Q5.Can I use this for JSON5 or JSONC (with comments)?
No — this tool uses standard JSON parsing which does not support comments or trailing commas. Remove comments and trailing commas before formatting.
Q6.What are common use cases for a JSON formatter?
Debugging API responses: paste a raw API response to quickly read its structure. Validating config files: catch typos in package.json, tsconfig.json, or CI config files before they cause build failures. Sharing readable data: format JSON before pasting it into documentation or a code review. Reducing payload size: minify JSON before embedding it in a web page or sending it to a client.
Q7.Can I format nested or deeply-indented JSON?
Yes. The formatter handles arbitrarily deep nesting. The default indent is 2 spaces, which matches most style guides (Prettier, ESLint defaults). The output is standard-compliant JSON that can be parsed by any JSON library.
Contact us to advertise here
// FAQ
FREQUENTLY ASKED QUESTIONS
Q1.Is my JSON data sent to a server?
No. All formatting and validation happens locally in your browser using JavaScript's built-in JSON.parse(). Your data never leaves your device.
Q2.What errors will the validator catch?
Any syntax error that makes JSON invalid: missing commas, unclosed brackets, trailing commas, unquoted keys, single quotes instead of double quotes, and more. The error message will show the position where parsing failed.
Q3.What's the difference between Format and Minify?
Format (prettify) adds indentation and line breaks to make JSON human-readable. Minify removes all whitespace to produce the smallest possible file size — useful for APIs and production data.
Q4.Is there a size limit?
No enforced limit, but very large JSON files (10MB+) may be slow to process depending on your browser and device.
Q5.Can I use this for JSON5 or JSONC (with comments)?
No — this tool uses standard JSON parsing which does not support comments or trailing commas. Remove comments and trailing commas before formatting.
Q6.What are common use cases for a JSON formatter?
Debugging API responses: paste a raw API response to quickly read its structure. Validating config files: catch typos in package.json, tsconfig.json, or CI config files before they cause build failures. Sharing readable data: format JSON before pasting it into documentation or a code review. Reducing payload size: minify JSON before embedding it in a web page or sending it to a client.
Q7.Can I format nested or deeply-indented JSON?
Yes. The formatter handles arbitrarily deep nesting. The default indent is 2 spaces, which matches most style guides (Prettier, ESLint defaults). The output is standard-compliant JSON that can be parsed by any JSON library.
// RELATED TOOLS
Convert images (PNG, JPG, WebP, PDF) and videos (MP4, MOV, AVI, WebM, GIF, MP3) instantly in your browser — nothing uploaded.
Generate QR codes for URLs, text, WiFi, email, and phone. Custom colors, gradients, and dot styles.
Count words, characters, sentences, paragraphs, and reading time instantly. Includes word frequency analysis and unique word count.