Paste JSON to pretty-print, minify, and validate it instantly in your browser.
Updated
/ 5 - Be the first to rate this tool Thanks for rating!
Verification failed - please try again.
Quick check
Please verify you're not a robot to submit your rating.
Give feedback
Tell us what you think about Format and validate JSON online.
- Runs entirely in your browser — your JSON is never sent to a server
- Pretty-print, minify, and validate, with the exact error location highlighted
- Free, no account required
How it works
-
1
Paste the code or data you want to format.
-
2
Choose pretty-print or minify, and set the indent width if you like.
-
3
The formatted result updates instantly.
-
4
Copy the result, or download it as a file.
Why use this tool
Every dev utility, one place
Format, convert, encode, decode, and generate — no more juggling ten tabs.
100% private, always
Every tool runs in your browser — your code and data are never sent anywhere.
Works on any device
Runs on Windows, Mac, Linux, iOS, and Android — nothing to install.
Instant results
No queues, no build step — results update as you type.
Built to handle real data
Full Unicode support and RFC-compliant parsing, edge cases included.
Free, always
Free to use, with no rate limits, sign-up, or trial period.
Frequently asked questions
Yes, it checks for missing commas, trailing brackets, and quotes, highlighting exactly where parsing fails.
By default, it uses standard 2-space indentation to keep the output compact and readable.
Because formatting relies on browser memory, massive payloads (over 5MB) may cause slight rendering delays.
It attempts strict parsing first; if it detects loose JavaScript objects, it will try to correct them into valid JSON.
Yes, object keys are kept in the exact sequence they were provided unless you explicitly choose to sort them.
From the blog
Reading a JWT Without Trusting It: Claims, Expiry, and the Signature Trap
Decoding a JWT takes a second. Verifying one is a different job entirely — and confusing the two is how auth bugs ship. Here is how to read a token safely while you debug.
Mastering Base64: What It Is, How It Works, and When Not to Use It
Base64 is everywhere in modern web development, from data URIs to authentication headers. Here is a deep dive into how it works and common pitfalls to avoid.
Demystifying JSON: How to Troubleshoot Common Parsing Errors
JSON is the backbone of web APIs, but syntax mistakes can halt your code. Here is how to identify and fix missing commas, unescaped strings, and trailing characters.
Recently viewed
Related tools
Format and minify CSS online
Pretty-print or minify CSS instantly in your browser, with adjustable indentation.
Format and beautify HTML online
Pretty-print or minify HTML instantly in your browser, with adjustable indentation.
Format and minify JavaScript online
Pretty-print or minify JavaScript instantly in your browser, correctly handling strings, template literals, regex, and comments.
Format and beautify SQL online
Pretty-print or minify a SQL query instantly in your browser, with clause-based line breaks.
Format and beautify XML online
Pretty-print or minify XML instantly in your browser, with adjustable indentation.
Format and re-indent YAML online
Normalize inconsistent YAML indentation to a consistent width instantly in your browser.
Validate JSON against a JSON Schema
Paste a JSON document and a JSON Schema to see every validation error with its instance path. Supports draft 2020-12 and draft-07, entirely in your browser.
Generate TypeScript interfaces and PHP classes from JSON
Paste JSON and get TypeScript interfaces or PHP classes with typed properties, including nested objects and arrays, instantly in your browser.
Decode a JWT online
Paste a JSON Web Token to instantly view its decoded header and payload in your browser.
Build and sign a JWT online
Build and HMAC-SHA256-sign a JWT from a header, payload, and secret, instantly in your browser.
Sort and de-duplicate lines online
Sort lines alphabetically or by length, remove duplicates, and strip blank lines, instantly in your browser.
Resize an image to LinkedIn post size for free
Fit or fill an image to the 1200×627 LinkedIn post size, with drag-to-reposition and zoom, right in your browser.