We are building a business data mashup for Business intelligence for SME. We are a team of two. While the core is almost ready, we haven't done anything on the client management system so far. That includes- payment, customer management, customer support,referral etc. I have experience with Magento customization, but it seems overkill for managing only 3-4 plans and expected gradual increase of clients to at most few thousands in the near future. However, the standard security practices are most important as the clients are mostly companies.<p>That makes me wonder- Do people build these from scratch? What are the effective customer management systems out there to handle sell, client management, and support for SaaS? possibly open source?
For payments just use Stripe.<p>SuiteCRM is a very polished open source CRM package you can host yourself with a ton of features and plugin modules. Might be what you're looking for.<p>There are also a bunch of online solutions you can search for. CRM is not your core business, so my advice would be to just outsource it to some online outfit, make sure you can migrate off it when you grow, and get on with your business.