Developer Tools
10 free tools
Everyday developer utilities: Base64 and URL encoding, JWT decoder, regex tester, cron expression builder, UUID generator and Markdown formatter.
Small utilities for everyday development work: encode and decode Base64 and URLs, inspect the contents of a JWT, test a regular expression, build a cron schedule, generate UUIDs and tidy Markdown. Each one has a guide that explains what it does and where its limits are.
Everything runs in your browser, so the text you paste is not uploaded. Decoding a JWT shows its contents but does not verify the signature, so do not treat the result as proof that a token is valid. The guides spell out limits like this for each tool.
Code Formatters1
Code Validators1
Encoders & Decoders4
Base64 Encoder
Encode any text into Base64 using the browser-native btoa() function, with full Unicode/UTF-8 support.
Base64 Decoder
Decode Base64 back to readable text using the browser-native atob() function, with full Unicode/UTF-8 support.
URL Encoder
Percent-encode text for safe use in URLs, or decode it back, using the native encodeURIComponent/decodeURIComponent functions.
JWT Decoder
Decode a JWT header and payload to readable JSON — a pure decode with no expiry or signature checking.
Generators3
UUID Generator v4
Generate a random RFC 4122 version 4 UUID with the version and variant bits set correctly.
SHA-3 Hash Generator
Generate SHA3-224, SHA3-256, SHA3-384 and SHA3-512 hashes of any text in your browser. Uses the standard NIST SHA-3 (Keccak) algorithm and shows all four digests at once.
CRON Expression Generator
Build a real cron expression from 5 comma-separated fields (minute, hour, day, month, weekday), with a plain-English schedule description.