I am looking to send emails from my monitoring service using the domain I have set up on ProtonMail. It would be easier/more secure to have email for my domain sent through ProtonMail's servers. I am not looking for a high volume of email, just a handful of nightly status emails (~5-10). Rather than misappropriate the ProtonMail Bridge software, I'd like to use an API so that I can programmatically send emails on the terms the ProtonMail team deems to be reasonable for API-based mail sending. API-based mail send allows for a more intelligent approach to sending email as an API-based solution should be able to respect the boundaries set by the API in terms of rate limiting and general usage. An API would also be a more secure solution than simple SMTP transmission.

I, too, would like to see an API, which would be useful for a webapp I'm building. Any updates from the development team?

Even if this could be implemented/exposed in stages. Case in point, I have an elaborate sieve filter that I want to update. I'd really prefer to just be able to craft a command to add/remove lines to it (or update the entire rule, which I could maintain offline), but right now my only option is to copy/paste a file into an online form.

Same with adding contacts to my personal address book.

This is also essential functionality to any sort of email automation e.g. Firing a webhook upon receiving a certain subject line - but I understand how that has more sensitive and complex than just maintaining flat records of contacts and sieve rules.

Open the Protonmail API. I think it would be good if third part developers could implement their own client. It would be great if we were not bound to a single client.

would love this too! any reply from the team?

An api would allow me to integrate secure email on my portal.

Without a doubt this is the best secure email service I've encountered. Only the absence of an api keeps it from earning an editors pick on my site http://resistancejax.net16.net/

https://www.sendinc.com/ offer such an API

Yeeees, I would really like to see the API for ProtonMail.
It is the only thing that puts other email providers ahead from you. If you could only give us the API my dream will come true :D

I would also like this. I am evaluating ProtonMail. I like it, but an API would be very useful -- especially because it ProtonMail does not support IMAP or SMTP.

I would create a contact sync app with Google and iCloud

It would also allow people writing plugins for outlook, thunderbird, etc.

I would love to see a API, so to create free secure emails etc or maybe a way to upgrade to premium and set-up the domains etc.

I really like this idea. Open APIs would as Ugnius B suggested, make it possible for the community to develop additional functions or programs, even to additional platforms.

It should though be thought through thoroughly, if this could compromize security. If it doesn't, then please give us open API or even open source resources.

It also could allow to free you from the task of writing email clients and let the community do that.