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I'm looking for an email (outgoing only) provider that has an API. I'd be sending probably ~100 a month, maybe. The reason is because microcontrollers have a hard time with TLS and whatnot, but CURLing to an API isn't that big of a deal.

I know sendgrid offers something like this as a freemium service, but free services sometimes don't work well. Is there a service that has a very limited, cheap plan but would still offer some support if needed?

I'm looking for an email (outgoing only) provider that has an API. I'd be sending probably ~100 a month, maybe. The reason is because microcontrollers have a hard time with TLS and whatnot, but CURLing to an API isn't that big of a deal. I know sendgrid offers something like this as a freemium service, but free services sometimes don't work well. Is there a service that has a very limited, cheap plan but would still offer some support if needed?

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[–] 2 pts

Take a look at smtp2go.

[–] 1 pt

I'm interpolating requirements here a bit but if Arduino then these devices are probably running in untrusted networks? If in a trusted network you could always stand up a mail gateway for them with relay access ACL'ed to the specific hosts or networks.

I think any sort of REST API-as-mail-relay is probably going to require TLS as well.

[–] 0 pt

More than likely it will require some sort of secure access, but I was hoping there would be a library pre-made for some sender, similar to what people have done for Telegram. Sendgrid has some stuff, but I'm not interested in using nodeJS or other cruft.

My goal is to have a device that is completely standalone and sits outside my network - either on someone else's and/or on my fallback cellular network - and checks to see if my network resolves, and tell me when it doesn't. I want as simple a device as possible, so having something like a postfix server running as a relay isn't my goal. It has to be able to recover from a hard power cut without intervention.

[–] 0 pt

I use C# and it talks to any smtp server. It has authentication too. There are a ton of options.

[–] 2 pts

Many uCs don't have the memory or performance to do TLS. His shortcut is to want a REST API which relays for him.

Personally I believe something like mqtt to his own server which then relays is a better option.

[–] 1 pt

I'm limited to arduino c++ for this project.

[–] 0 pt

SMTP is an api and has plenty of libraries, including authenticated SMTP

[–] 0 pt

The arduino doesn't really have the horsepower to negotiate SSL connections.

You're probably not going to find anyone that doesn't have some kind of secure connection. Maybe find someone that supports shell accounts and pipe it through ssh, or something.

I've used eskimo.com in Seattle for 20 years for doing non-standard stuff.