We currently support two file formats, and are actively extending support. Gerber X2 with extended comments generated from KiCAD or IPC2581B files exported from Altium Designer, Zuken's CADSTAR, Mentor PADS, OrCAD, Allegro PCB designer, and Pulsonix. We also support Eagle through importing your project into KiCAD first and exporting the gerbers from there.
To render more rich information, you can optionally use your BOM populated with manufacturers part numbers too.