OAuth 2.0 is a widely used specification for authorization aspects of resources in a light weight manner. WSO2 Identity Server provides a comprehensive implementation of this specification.
This section provides instructions on how to work with OAuth2 to expose resources in a secure manner.
About the length of Access and Refresh tokens
Note that a UUID is created as the access token with the default size is 36 characters. The maximum size can be 255 which is the column size of ACCESS_TOKEN (in database table IDN_OAUTH2_ACCESS_TOKEN). Same applies to refresh token length.