Uhm, surprised no one has mentioned https://invoiceplane.com/ https://invoiceplane.com/ yet, which is the first thing that comes up if you google "open source i

Uhm, surprised no one has mentioned https://invoiceplane.com/ https://invoiceplane.com/ yet, which is the first thing that comes up if you google "open source invoice". For my purposes free doc templates (in my case Google Docs) serve my invoicing purposes perfectly well though. Plain docs are also nice in that they're more flexible than a web based app.