http://kainr2.github.io/kitto/tools/js-decoder.html

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Encode Base64 Decode Base64 ... Encode Base64 URL Safe Decode Base64 URL Safe
URI Encode URI Decode ⇐ No encode/decode[:/;?] URI Component Encode URI Component Decode
Encode SAML (GET) Decode SAML (GET) Decode JWT Beautify Json Beautify XML

OUTPUT: Copy To Input Dark Theme

Changelog
    Version 1.2.1
    * Update UI - color buttons and dark theme
    Version 1.2.0
    * Fixed deflation of SAML and JWT
    Version 1.1.0
    * Use "pako.js" for SAML deflation
    * Error handling for JSON
    Version 1.0.1
    * Disable spellchecker
    * Resize input/output
    Version 1.0
    * Initial version
    * Based on -- https://github.com/kallu/SAMLdecode