Platycryptus magnus is a species of jumping spider in the family Salticidae. It is found in Central America, has a large hairy body and is mostly gray. They are very similar to other platycryptus, but differ from other members of their genus by having a moderate retrolateral tibial apophysis, a small bump on their pedipalp. Previously, Marpissa broadwayi was mischaracterized as a separate species but they are synonymous.