How do you add Persistent Authentication?

Sounds like you are mixing concerns. Guardian is used for JWT, so things like API pipelines and such. Users should (usually) still have a cookie session (whether that is by storing a JWT in it via Guardian or not…).

@OvermindDL1 Am I mixing concerts? I’m probably too spoiled from using Meteor’s Accounts library. Anyhow, is there an example on how to manage authentication in a cookie or LocalStorage?

IMHO, the cookie issued for you is session cookie. You have to set ttl for Guardian like these:

config :guardian, Guardian,
  ttl: { 100, :days },

I already have that set but I get logged out when I restart the browser.

Is there max_age in your Plug.Session? like lib/[your app]/endpoint.ex:

plug Plug.Session,
  store: :cookie,
  key: "xxxx",
  signing_salt: "xxx",
  max_age: 36000

omg… That’s it! Thank you so much!