st.experimental_user

st.experimental_user is a Streamlit command that returns information about the logged-in user on Streamlit Community Cloud. It allows developers to personalize apps for the user viewing the app. In a private Streamlit Community Cloud app, it returns a dictionary with the viewer's email. This value of this field is empty in a public Streamlit Community Cloud app to prevent leaking user emails to developers.

The API closely resembles that of st.session_state and st.secrets. It follows a field-based API, which is very similar to Python dictionaries.

Allowed fields

The st.experimental_user command returns a dictionary with only one field: email.

Display the allowed field by passing the command to st.write:

# Display the contents of the dictionary
st.write(st.experimental_user)

The above displays a dict with one field and value. The field is always email:

{
  "email": "value"
}

You can check if a field exists in st.experimental_user:

# Returns True if the field exists
"email" in st.experimental_user

# Returns False if the field does not exist
"name" in st.experimental_user

Read values

Read the value of the email field and display it by passing to st.write:

# Dictionary like API
st.write(st.experimental_user['email'])

# Attribute API
st.write(st.experimental_user.email)

The above outputs either None or the logged-in user's email or test@localhost.com, depending on where the app is running. Read further to learn about st.experimental_user's context-dependent behavior.

Updates and modifications

Keys and values for st.experimental_user cannot be updated or modified. Streamlit throws a handy StreamlitAPIException exception if you try to update them:

st.experimental_user.name = None
# Throws an exception!

st.experimental_user.email = "hello"
# Throws an exception!

Context-dependent behavior

The value of st.experimental_user.email is context-dependent. It returns a value depending on where the app is running. The private or public app can be running on Streamlit Community Cloud, locally, or on a 3rd party cloud provider. Let's look at the different scenarios.

Private app on Streamlit Community Cloud

Users need to be logged in to Streamlit Community Cloud to view private apps. If a user is not logged, they see:

If a user is logged in, st.experimental_user.email returns the user's email. Suppose a user logged in to Streamlit Community Cloud using jane@email.com:

st.experimental_user.email
# Returns: jane@email.com

Public app on Streamlit Community Cloud

Currently, st.experimental_user.email returns information about the logged-in user of private apps on Streamlit Community Cloud. If used in a public app, it returns None. For example:

st.experimental_user.email
# Returns: None

This value of this field is empty in a public Streamlit Community Cloud app to prevent leaking user emails to developers.

Local development

When developing locally, st.experimental_user.email returns test@localhost.com. We don't return None to make it easier to locally test this functionality. For example:

st.experimental_user.email
# Returns: test@localhost.com

App deployed on a 3rd party cloud provider

When deploying an app on a 3rd party cloud provider (e.g. Amazon EC2, Heroku, etc), st.experimental_user.email behaves the same as during local development. For example:

st.experimental_user.email # On a 3rd party cloud provider
# Returns: test@localhost.com

Examples

The ability to personalize apps for the user viewing the app is a great way to make your app more engaging.

It unlocks a plethora of use-cases for developers, some of which could include: showing additional controls for admins, visualizing a user's Streamlit history, a personalized stock ticker, a chatbot app, and much more. We're excited to see what you build with this feature!

Here's a code snippet that shows extra buttons for admins:

# Show extra buttons for admin users.
ADMIN_USERS = {
    'person1@email.com',
    'person2@email.com',
    'person3@email.com'
}
if st.experimental_user.email in ADMIN_USERS:
    display_the_extra_admin_buttons()
display_the_interface_everyone_sees()

Show different content to users based on their email address:

# Show different content based on the user's email address.
if st.experimental_user.email == 'jane@email.com':
    display_jane_content()
elif st.experimental_user.email == 'adam@foocorp.io':
    display_adam_content()
else:
    st.write("Please contact us to get access!")

Greet users with their name that's stored in a database:

# Greet the user by their name.
if st.experimental_user.email:
    # Get the user's name from the database.
    name = get_name_from_db(st.experimental_user.email)
    st.write('Hello, %s!' % name)

Caveats and limitations

• st.experimental_user is read-only. You cannot update or modify its value. Doing so will throw a StreamlitAPIException.
• A valid email is returned only if the user is logged in to Streamlit Community Cloud and the app is private. Else, None or test@localhost.com is returned.
• This is an experimental feature. Experimental features and their APIs may change or be removed at any time. To learn more, click here.