Docusnap is described as 'The easy way of Network Inventory and IT Documentation'. There are more than 10 alternatives to Docusnap for a variety of platforms, including Linux, Online / Web-based, Windows, Self-Hosted solutions and Mac. The best alternative is Snipe-IT, which is both free and Open Source. Other great apps like Docusnap are NetBox (Free, Open Source), GLPI (Free Personal, Open Source), Ocsinventory-ng.org (Free, Open Source) and Foreman (Free, Open Source).
NetBox is an open source web application designed to help manage and document computer networks. Initially conceived by an engineering team at DigitalOcean, it was developed specifically to address the needs of network and infrastructure engineers.
GLPI is an IT Service Management software based on open source technologies. It is a suite for IT, project, financial and user management. GLPI can support companies of any size, and offers both on-premises and cloud (SaaS) solutions.
Racktables is a nifty and robust solution for datacenter and server room asset management. It helps document hardware assets, network addresses, space in racks, networks configuration and much much more!