A: Hi,

It's Alex, the founder of ProxiedMail.
Thank you for your question.

It's possible to reply to the incoming message, but not possible to send first via API.
Please see the application and request example on the Github:

https://github.com/proxied-mail/ai-bot/blob/main/http/ReplyToMessage.ts

I don't think we would implement sending the first email via API since we're not building the transactional email.

Let me know if you have a further questions.
Thank you.