Developer Tools
Free online developer tools to format JSON, encode Base64, encode URLs and generate UUIDs.
Day-to-day developer utilities that keep everything local: format and validate JSON, encode and decode Base64, encode URLs, sort and transform text, and generate UUIDs and random values.
JSON Formatter
Free JSON formatter, validator and minifier. Pretty-print, compress and check JSON syntax instantly in your browser.
Base64 Encoder & Decoder
Free Base64 encoder and decoder for text. Encode and decode UTF-8 strings instantly, right in your browser.
UUID Generator
Free UUID v4 generator. Create one or up to 100 unique identifiers with cryptographically-secure randomness, in your browser.
URL Encoder & Decoder
Free URL encoder and decoder. Percent-encode query parameters or decode an encoded URL back to readable text.
Frequently asked questions
How do I fix invalid JSON?
Paste the fragment into the JSON formatter. Common issues are trailing commas, unquoted keys, single quotes or comments. The formatter highlights where parsing fails so you can correct the source.
What is Base64 and when is it used?
Base64 encodes binary data into plain ASCII text, commonly used for embedding images, tokens or credentials in URLs and messages. Remember it is encoding, not encryption: anyone can decode it.
What is the difference between UUID v4 and other versions?
UUID v4 is random and is what most web apps use. Other versions derive the identifier from a timestamp or a namespace. For general use, a v4 UUID gives you 122 bits of randomness.