monapi.io is described as 'IP, Email & Domain Threat and Geolocation API'. There are six alternatives to monapi.io for a variety of platforms, including Online / Web-based, SaaS, Self-Hosted solutions, Mac and Windows. The best alternative is ipinfo.io, which is free. Other great apps like monapi.io are ProxyCheck.io (Freemium), ipapi (Freemium), Ipregistry (Freemium, Open Source) and Apility.io (Freemium).
Apility.io is a Threat Intelligence SaaS for developers and product companies that want to know in real-time if their existing or potential users have been classified as 'abusers' by one or more public blacklists.