Zervant is a really nice tool to write your invoices with. They react to changes in German law and I suppose they likewise care for other countries’ legislation.

For those of us, who write just a handful of invoices per month, this is cool (and free!): the invoice is customisable to a degree (logo, e.g.). Zervant helps you to track payments, so you get a clear overview of what is happening.

I miss a calender to register contracts, so I get reminder of the invoice that needs to be written, e.g. for a long running support contract to be paid in chunks. I’d also love Google authentication. Then again, for invoices, maybe it is better as it is.

I just like it, with the scope that I have, it is for free. Cool and professional!