Data binding is a widely used concept inside Toolpad apps. It allows for connecting various parts of the application and making them react to data changes.
In order to initiate data binding, look around in the UI for a binding button:
The easiest way to tell if a value can be made dynamic is by locating this binding button, i.e. the Text Field component allows you to bind every property that you could otherwise control manually.
At the top of the editor you can see an explanation of what type of property we expect to be defined (i.e. above mentions string).
On the left side of the editor there is a list of all the variables in the scope that can be used to define the expression.
All that's left is to click Update binding and you can observe how the application behaves.
(In this example you can see TextField value bound to the value of Typography component).
Field with value:
Certain properties, such as HTTP request headers, can also be bound to environment variables.
In the binding editor for such properties, the Environment variable tab will be available, where any environment variable currently in the project can be selected.
You can safely store secrets in environment variables and use them in this type of binding, as the values of environment variables are only used serverside.