Free Online Developer Tools
Every developer keeps a mental drawer of small utilities — format some JSON, decode a Base64 string, generate a UUID, hash some text, inspect a JWT, test a regex, convert a timestamp. Reaching for a random website for each one is slow and, for anything sensitive, risky. This cluster gathers the essentials as fast, private, in-browser tools, and this guide is the reference for when and why to use each.
All developer tools
Guides & tutorials
URL Encoding Explained (When and Why to Percent-Encode)
What %20 and %2F actually mean, when you need to encode a URL, and how to encode or decode query strings correctly — with the component vs full-URL distinction.
5 min readWhat Is a UUID? (And How to Generate One Safely)
UUIDs are the unique IDs behind modern software. Learn what they are, why v4 is the one you usually want, and how to generate them securely in bulk.
5 min readHow to Generate a Hash (SHA-256 and Friends), Explained
What a hash is, why SHA-256 is everywhere, why MD5 is dead, and how to generate a hash from text in your browser for checksums and fingerprints.
6 min readHow to Decode a JWT (and What Each Part Means)
JSON Web Tokens power modern auth. Learn how to read the header, payload, and claims of a JWT — and why decoding is never the same as verifying.
6 min readHow to Test a Regular Expression (Without Losing Your Mind)
Regex is powerful and famously fiddly. Learn a practical way to build and test patterns, understand flags, and debug matches in real time.
5 min readUnix Timestamp Converter: Epoch Time Made Simple
What a Unix timestamp is, why software stores time as a number, and how to convert between epoch seconds and human dates — in seconds or milliseconds.
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