Customer management and billing system to be developed in PHP/MySQL

We are a small web host and We require a developer to build us an all-in-one client manager and billing system in PHP with a MySQL database back end. The developer must have experience integrating payment gateways (preferably with HSBC UK eSecure Payments gateway). Experience of the Enom domain registrar API and Nominet email PGP domain automation would be a bonus. The system MUST be: - Flexible, Stable and Secure. - Future proof (easily upgradeable, easy to add new features to) - We may require new modules to be written in the future, and these would ideally be easy to install, so the main framework needs to be adaptable to any future requirements. - Due to the system storing client information, it is imperative that security is the highest priority. This system will hold all our client data and billing information so the developer needs to be conscious of security when coding all aspects of this project. - Stability is also key. We cannot afford the system to fall over at any point. We expect the system to hold tens of thousands of records. The system will be used on a daily basis and is therefore mission critical. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform The system must run on a Linux (CentOS) based platform and be developed in PHP / MySQL with Java where necessary.