UX writing is the work of writing the words inside a product so that a person can do what they installed it for: place an order, pay a bill, book a doctor, send money. An ad persuades someone to install the app. Interface copy guides them once they are in.
When it works, nobody notices it. A person taps a button and gets what the button said. The copy becomes visible when “Next” leads somewhere unexpected, an error says “Something went wrong,” and an empty screen says “No data.” Then the team doesn't get conversions. It gets support tickets and uninstalls.
What the field is called
People search for “UX writing,” “UX copywriting” and “microcopy,” and inside product teams you'll hear “content design” as well. For the purposes of an order they all mean the same thing: short, functional text on screens. We use all the names on this page because clients look for us under different ones.
App, application, product
We write for iOS and Android apps, and just as often for web products with a login: customer accounts, booking forms, admin panels, internal tools. The principles are the same, and so is the price per screen.