WHMCS!

BILLmanager is a linux-based control panel for automating client management, invoicing and billing. This software specifically developed for hosting service providers will help you manage and take complete control of various aspects of your business:

Nukern is an automated billing and cloud provisioning platform for web hosts and digital agencies. It automates the recurring invoicing and the re/selling of cloud & web hosting services. In a couple clicks, you can link your servers to our platform and be online with your Nukern storefront, ready to sell hosting services to all your clients.

Complete client management, billing & support software. BoxBilling is free and will always be free! You can sell any product imaginable - web hosting, software licenses, servers, downloadable products and setup any custom products.

Have your staff manage support tickets painlessly and quickly. Prevent emails and support issues from getting lost. ClientExec's email management system helps you route, track and deliver messages.

Blesta is professional client management, billing, and support software. Modular design means Blesta works for a wide range of business types including web-hosting companies, web designers, developers and many more.

Ubersmith is:

Atomia was founded in 2009 by a group of hosting industry veterans who wanted to build a flexible, modular, and scalable hosting software platform with powerful service automation, something they felt no one had really managed to achieve yet.

ZBilling Net is a Free ASP.NET MVC Billing solution not just for WebHostings and Freelancers, but for everyone that are looking for a recurring billing software.

Manage your own Hosting Company by ShineISPbilling software – Domain Management – Free Open Source – New BSD license

HostBill is fast and efficient client management, support and billing web based software for hosting and online companies. HostBill can make your life easier from client signup, through account automated provisioning, support and billing to termination. Automate your business with HostBill.

BillingServ provides hosting companies & small businesses with a software as a server billing system designed to increase ease of billing, cut costs and increase stability as BillingServ is hosted in the cloud.

RackNap is a Cloud Service Delivery and end-to-end Business Cycle Automation platform for cloud, datacenter, telco and hosting industry. Enabling providers to sell cloud services on their own infrastructure, as well as via third party providers like Microsoft, Amazon, Google and IBM. RackNap covers all facets of business operations – sales and marketing, billing, inventory management, support, marketplace and multi-tier partner management – all backed by business intelligence.

Parallels Business Automation Standard offers a comprehensive cloud billing and automation solution for scaling mid-size web hosting operations, and delivering complete customer lifecycle management.

With it's many built in features AWBS is truly an instant hosting company platform containing all the essential tools for providers to signup, bill, maintain and support clients using a single interface.

TheHostingTool was launched on the 3rd of December 2008 aiming to provide the next generation in free, hosting applications. It provides you, the webhost, near complete automation on everything you want it to do. So that means, signup, monthly posts checking, suspension, and termination. While it does that, it provides client features, like the client control panel that gives the clients the power to manage their account. In addition, they can check their monthly forum posts, edit their details, and check announcements. TheHostingTool also has relatively frequent updates and great support from a growing community. »