At the moment, Sympli Handoff supports iOS, Android and Web projects (with multiplatform projects coming soon), and each platform lets you select multiple resolutions.
Resolution of the project in Sympli Handoff is based on the size of your mockup and means the baseline you created the mockup in. Let’s look at an example:
If you’re working on an iOS app for the iPhone 6, you have the following options for artboard sizes:
375x667, which stands for @1x in Sympli
750x1334, which stands for @2x in Sympli
and 1125x2001, which stands for @3x in Sympli
In Sketch, if you use standard artboard templates, always choose @1x (mdpi for Android projects).
In Photoshop, the standart artboard templates are in @2x (xhdpi for Android) baseline, so choose corresponding project resolution in Sympli Handoff. But we really encourage you to practice designing at @1x, as it's more flexible approach.