Easy Authentication with Google & Auth0 Guide

I need to secure my Streamlit micro SaaS, because a girl needs to track users and build that newsletter list.

Any self-respecting developer needs to have authentication and if you are building a software as a service product, you need to provide different ways for your users to login.

I was able to find a tutorial on YouTube regarding using Google and it was helpful, but another part of the tutorial actually used Auth0.

I love watching YouTube tutorials like every other developer out there, but I actually prefer to have it written down so this is my take on the tutorial. The video on which this article is based was very well recorded and very helpful so I’ve linked it here, so that you can give this content creator some well-deserved views.

So the reason why I need to figure out how to implement the authentication for my software that I built on Streamlit is, because I need to track users and I also want to lock down the code as well.

There are a lot of free applications on Streamlit, but I really want to be able to make this as realistic as possible, so I can actually call it a micro SaaS.

So let's dive in.

Authentication Setup for Google

Setup a new project in Google Cloud

Or if you already have a project, create a new one:

Search for ‘Client’ and select Clients:

You have to configure your application’s identity so you’ll be made to do:

Then can you NOW create the OAuth client:

I am creating a web application:

Then, give it a name:

Make sure to copy the secret, because you will not be able to see it again if you close the dialog!

Here it is:

Then setup your .streamlit/secrets.toml file:

[auth]
redirect_uri=""
cookie_secret=""

[auth.google]
client_id="add the google id here"
client_secret="add the google secret here"
server_metadata_url=""

Connecting it all

Setup the redirect URIs, set it to http://localhost:8501/oauth2callback:

And then paste it to your secrets.toml file:

[auth]
redirect_uri="http://localhost:8501/oauth2callback"
cookie_secret=""

[auth.google]
client_id="add the google id here"
client_secret="add the google secret here"
server_metadata_url="https://accounts.google.com/.well-known/openid-configuration"

Then have Claude Code generate a random secret key for the COOKIE_SECRETS:

If you are going to host this on Streamlit Cloud or your own server (other provider like Render) you have to provide the FULL URL. (I'll update this once I get it on to Render). But basically you will need to enter the URI redirect link from your Render application.

Now need a metaserver url

Go to Google’s Discovery document and paste it in your secrets.toml file:

[auth]
redirect_uri="http://localhost:8501/oauth2callback"
cookie_secret="claude-generated random secret here"

[auth.google]
client_id="add the google id here"
client_secret="add the google secret here"
server_metadata_url="https://accounts.google.com/.well-known/openid-configuration"

Add the code

Make sure to add the library: uv add authlib

uv add authlib

Add the code to for the authentication:

import streamlit as st

st.subheader("**Authenication**")

if st.button("Login"):
    st.login("google")

st.json(st.user)

This will keep your user signed in for 30 days.

You can add test users and when you are ready to publish it, make sure to have a logo for it:

Authenication with auth0

And then create a new “Regular Web Applications”:

Go to the Settings table and copy the Domain, client id and secret:

Add this in your secrets.toml file:

[auth.auth0]
domain=""
client_id=""
client_secret=""
server_metadata_url="https://{your domain name from above}.com/.well-known/openid-configuration"
client_kwargs = { "prompt" = "login"}

Then add the callback to the Application URIs section under Allowed Callback URLs:

Connect the Google Cloud to Auth0, by going to the Applications tab and selecting Authentication to create a new Connection:

Select Google/Gmail:

Go to Google Cloud and add the client id and the Client secret (or just copy from your secrets.toml file for these:

Then go to Google Cloud to add your Auth0 domain under authorized Javascript origins and redirect URIs, which should be something like this: https://{your_auth0_client_name}.us.auth0.com/login/callback

Then under the Branding Section, add auth0 as an Authorized Domain:

Make sure to look at your Applications and turn it on for your app:

And now, Auth0 and Google can tango!

Then edit the code in your app to use auth0 instead of Google:

if not st.user.is_logged_in:

    if st.sidebar.button("Log In"):
        st.login("auth0") # st.login("google")
else: 
    if st.sidebar.button("Log Out"):
        st.logout()
    # Initialize email if it doesn't exist in session state
    if "email" not in st.session_state:
        st.session_state["email"] = st.user.email

st.json(st.user)