>Think, you're developing your application with an easy language more easy than VFP and you have all basic modules (customer, invoice, finance, >accounting, invent...) and you can full customise all modules. You don't need write an ERP or connect an ERP because you're writing in an ERP...

That's what xTuple is - an ERP app. The nice thing about xTuple (besides it being open source) is most of the code I need is in the database (Postgres). And the code that is not, I can access via QT script (javascript) or just copy. So just as you said - I have customer,invoice,finance, accounting, inventory... all within xTuple. I also have complete manufacturing, a lousy POS, some distribution, and several third party modules.

If your customer is a "ma and pop" shop xTuple is free with Postbooks. If not - it cost. But not anything near what it cost for other ERP solutions.

So, this is what I do. I develop the program in python (Dabo) that accesses the xTuple Postgres API schema (a bunch of read-write views) for 90% of the features and the other 10% I use either one of the 1331 functions that are available or write my own - all on the database side.

Johnf