JSON Formatter
Format, validate, and beautify JSON online with syntax highlighting
Open ToolDeveloper
13 tools · JSON formatter, Base64, UUID, hash generator, JWT decoder and more
Development workflows are full of small but time-consuming transformations: formatting a JSON payload for readability, decoding a JWT to inspect its claims, converting a Unix timestamp to a human-readable date, generating a UUID for a database record, minifying CSS for a production build, encoding a binary file as Base64 for an API request, or converting between number bases for low-level debugging. The developer tools in this section automate all of these tasks. Each tool is designed to be keyboard-first and copy-paste friendly — paste your input, get the output in one click, and move on. All processing happens in your browser with zero server round-trips, so sensitive data like private keys, API tokens, JWT secrets, or proprietary JSON schemas never touches an external server. The tools are designed for software engineers, DevOps professionals, and anyone who regularly works with data formats, encodings, and cryptographic primitives.
Frequently asked questions
What is Base64 encoding and when should I use it?
Base64 is an encoding scheme that converts binary data into a string of ASCII characters. It is not encryption — Base64 encoded data can be decoded by anyone. Use Base64 when a transport protocol or data format only supports text, such as embedding a small image in CSS, encoding a binary file in a JSON payload, or constructing a Basic Authentication header. Do not use Base64 to hide or protect sensitive data; use proper encryption instead.
How do I decode a JWT without a secret key?
A JWT consists of three Base64-encoded parts separated by dots: header, payload, and signature. The header and payload can be decoded without the secret key because they are only Base64-encoded, not encrypted. The JWT decoder tool decodes these two sections so you can inspect the claims — user ID, roles, expiration time — without verifying the signature. To verify the signature, you need the secret key or the issuer's public key.
What is a UUID and why use them instead of sequential IDs?
A UUID is a 128-bit identifier formatted as eight groups of hexadecimal digits separated by hyphens. Sequential database IDs (1, 2, 3…) expose your record count and are easy to iterate — a malicious actor can enumerate all users by incrementing the ID in a URL. UUIDs are effectively impossible to guess, making them safer for user-facing identifiers. UUID v4 is randomly generated; UUID v5 is deterministic — the same namespace and name always produce the same UUID.
When should I use a hash function versus encryption?
Hash functions (MD5, SHA-256, SHA-512) are one-way transformations — you cannot recover the original input from the hash. Use them for data integrity verification (checking a downloaded file), password storage with a salt, or generating a content fingerprint. Encryption is two-way — data can be decrypted with the correct key. Use encryption when you need to recover the original data later. Never use MD5 or SHA-1 for password storage; use bcrypt, Argon2, or scrypt instead.