The first visible-blind UV photodetector based on MAPbCl(3) integrated on a substrate exhibits excellent performance, with responsivities reaching 18 A W-1 below 400 nm and imaging-compatible response times of 1 ms. This is achieved by using substrate-integrated single crystals, thus overcoming the severe limitations affecting thin films and offering a new application of efficient, solution-processed, visible-transparent perovskite optoelectronics.