Like it says on the tin,I’m an IT consultant. One of the things I need to do my job is a decent invoicing system –and,importantly,one that’s internet-friendly –I need to be able to access it from anywhere via the internet,and I need to be able to email invoices. Because of the very agile nature of a small IT consulting business,I absolutely need the ability to write one-off invoices “on the fly”as well,without depending on inventory or long look-up tables of specific parts or services. That said,I do also offer monthly and annual service and/or hosting agreements to customers,which I have been (actually,my lovely bookkeeper has been) banging out manually each month/year/whatever until now. And some parts and services change infrequently enough that it would be nice to just pick those from a list –particularly if I can override the default pricing set if I need to. So it would be a giant plus for my invoicing application to gracefully handle recurring billing and pre-configured line items as well as one-offs. There are quite a lot of subscription services which do this kind of thing as a hosted service,but being who I am,I much prefer to host it myself –and if at all possible,I prefer an open source solution as well. Unfortunately,while there are quite a lot of them to choose from,they’re all pretty flawed in one way or another. Listed below are the results of my search,with the one I eventually settled on listed last. [...]