Base64-Tool

This tool can encode and decode Base64 data.

Configuration:

encode/decode: Choose wether you want to decode or encode data
hexadecimal: When encoding, the input will be seen as binary data; when decoding, the output data will be displayed in its hexadecimal representation
urlsafe: Use the Urlsafe Base64 alphabet

The tool completely runs in your browser without any external dependency or API needed. You could simply Ctrl+S to download it, and open the file with your browser.