Free toolDeveloper

JSON Formatter & Validator

Pretty-print, minify and validate JSON with clear error messages.

About this tool

JSON from an API or log is often a single dense line that's painful to read. This tool reformats it with the indentation you choose, or strips all whitespace to minify it for transport.

It also validates as you type: paste anything and it confirms the JSON is well-formed or points to the syntax error. Everything runs locally, so even sensitive payloads never leave your browser.

Frequently asked questions

No. Parsing, formatting and validation all happen in your browser using the native JSON engine. Nothing is transmitted or stored.

More tools

View all

IP Address Lookup

Check the geolocation, ISP, organization and ASN of any IP — or your own.

Browser Fingerprint

See what every website can read about your browser, device and identity.

Password Generator

Create strong, random passwords with a live strength meter — all in your browser.

Subnet Calculator

Turn any IPv4 CIDR block into its network, broadcast, mask and host range.

User-Agent Parser

Decode any user-agent string into browser, engine, OS and device type.

IP Address Converter

Convert an IPv4 address between dotted decimal, integer, hex and binary.

Proxy List Formatter

Convert a proxy list between host:port, user:pass@host:port and more.

cURL Command Builder

Build a curl command with a proxy, custom headers, method and body.

Random User-Agent Generator

Generate realistic, up-to-date user-agent strings for desktop and mobile.

Base64 Encode / Decode

Encode text to Base64 or decode it back, with full UTF-8 support.

URL Encode / Decode

Percent-encode text for safe use in URLs, or decode it back.

JWT Decoder

Decode a JSON Web Token to inspect its header, payload and expiry.

Unix Timestamp Converter

Convert Unix timestamps to human dates and back, in seconds or milliseconds.

Hash Generator

Generate MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes of any text.

Password Strength Tester

Estimate a password's entropy and how long it would take to crack.

Passphrase Generator

Create memorable, high-entropy passphrases from random words.

UUID & API Key Generator

Generate v4 UUIDs or random API keys in bulk, securely in your browser.