Authentication with Dendrite is done via the extension 'Dendrite Vault'. It's a Chrome extension that extracts your session details from a specifed website so that your agent can log in your service on a separate browser.
This way, you never need to share sensitive details such as passwords with your agent.
Removing an agent's access for a website it easy – just delete the session in Dendrite Vault.
Read how to install and use the plugin here: https://docs.dendrite.se/examples/authentication-instagram