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Dynamic apps using hex_user_email

A dive into the hex_user_email built-in variable and how to leverage it to create dynamic apps.

tip

Check out the companion Hex project for this tutorial here!

This tutorial will go into detail on the hex_user_email built-in variable, and cover some examples for creating dynamic app experiences based on the its value. By the end, you'll be ready to create a single app that renders differently depending on who's viewing the published app!

What is hex_user_email?​

Hex has a few built-in variables that can be leveraged in the logic of your projects. One of these built-in variables is hex_user_email.

In published apps, the logged in user's email address will be stored as the hex_user_email variable. This makes this variable perfect for customizing what a given user sees in the app!

Some example use cases​

SELECT account, sum(revenue)
FROM sales_table
WHERE account_owner_email == {{hex_user_email}}
  • Execute dynamic Python code:
if hex_user_email in ('[email protected]', '[email protected]', '[email protected]'):
    department = 'engineering'
else:
    department = 'other'
{% if hex_user_email == '[email protected]' %}
Hi Jaylin!
{% elif hex_user_email == '[email protected]' %}
Hi Imani!
{% else %}
Hi there!
{% endif %}

hex_user_email and published app run settings​

When opening an app that is set to show results from a previous run, the initial app load will not use the hex_user_email variable as expected.

Why? Apps set to show results from a previous run automatically load using the cached results from the most recent app publish or scheduled run. Therefore, if you want hex_user_email to be set to the viewer's email address upon the app's initial load, you'll need change this setting to run the app from scratch.

hex_user_email in different run contexts​

Note: hex_user_email will only evaluate to the user's email address in the published app.

When viewing the project's Notebook view + App builder, the variable will always equal [email protected].

If an anonymous user (i.e., someone without a Hex account) views the published App, hex_user_email will be a random hash. An app will only ever have anonymous viewers if it's been made available publicly.

tip

Check out this tutorial's companion app to see how the hex_user_email value changes when viewing the logic vs. the published app.

Video example​

To drive this home, here's a quick video demo of what a published app that uses hex_user_email looks like from the perspectives of two different users!

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