One of the best resources for Xojo users is the more than 140 example projects.
Starting with Xojo 2023r4, it is even easier to find that specific example you need with new descriptions and filtering options.
Read more here: bit.ly/3RwGw79#Xojo#CodeSample
Se for api - se inspirar na Stripe
Se for tutorial ou codesample - Apple Developer
Code API - *eu* gosto da do MongoDB, acho claro e com exemplos as coisas mais usadas
Menção deshonrosa OCaml. Mas da JaneStreet é boa