A user agent is the identifier a web browser or email client sends to a server so it can introduce itself: Chrome on Windows, Outlook on Mac, Gmail on iPhone, etc. Mailpro reads this string when a recipient opens your campaign and uses it to power the device, browser and email-client statistics in your account.
What Mailpro extracts from it
From the user agent, Mailpro derives the operating system (Windows, macOS, iOS, Android), the email client or browser (Outlook, Gmail, Apple Mail, Chrome…), the device type for the desktop-vs-mobile split, and known bot signatures used to filter out automated pre-fetch opens.
Why these stats sometimes look strange
Modern email apps and corporate firewalls often pre-fetch images, which fires the open tracker before the human reads anything. Apple Mail Privacy Protection, in particular, pre-loads every image so opens get inflated. Mailpro filters known bot user agents, but no provider can detect 100% of them — expect a small margin of error. See why statistics can be incomplete or incorrect.
Where to see this in your account
Open any campaign report and look at the “Email clients” and “Devices” sections; the data is built from user agents collected when each open is logged. To dig deeper, combine it with click-through and hotspot reports.
Use the data to design better campaigns
If most opens come from mobile devices, prioritize short subject lines and a single-column layout. Check the device split in every campaign before designing the next one.