Access token terminology#

Base64url encoding

Base64 encoding with all trailing '=' removed, '+' changed to '-', and '/' changed to '_'.

For more information, see the IETF documentation on RFC 7515.

The following example is an implementation of base64url encoding in PHP:

function base64url_encoded($str)
{
    return rtrim(strtr(base64_encoded($str), '+/', '-_'), '=')
}

The following example is an implementation of base64url encoding in Python:

import base64
def base64url_encode(s):
"""Return a base64url-encoded str"""
return base64.urlsafe_b64encode(s).rstrip('=')

For an example implementation of base64url encoding in C#, see the IETF documentation on RFC 7515.

URL and filename safe string

A string composed of characters found in the URL and filename safe Base64 alphabet.

For more information, see the IETF documentation on RFC 4648.