Hack Club's been a fiscal sponsor for about 7 years now (since 2018), and it's evolved quite a bit since the early days. I run engineering & product for the fiscal sponsorship program there and would be happy to chat/share any tips!
oh, and while it's on my mind, the codebase was open-sourced earlier this year (>>43519802 ), and we just launched a mobile app yesterday! >>46130402