Spyse is described as 'A search engine which collects, processes, and provides structured information about network elements using an OSINT techniques. Provides detailed info on the following elements: DNS, AS, IPv4 Hosts, Ports, Banners, Digital Certificates, and more'. There are five alternatives to Spyse for a variety of platforms, including Online / Web-based, Self-Hosted solutions, Linux, Mac and BSD. The best alternative is ZoomEye, which is free. Other great apps like Spyse are Sublist3r (Free, Open Source), IVRE (Free, Open Source), BinaryEdge (Freemium) and Natlas (Free, Open Source).