Long time reader here. I wanted for a long time to build and publish something, so here it goes.

I built a temporary disposable email service. The backend is coded in C# (.Net Core 1.1) and runs on a small Linux VPS. The database is Postgresql. I did not bother using Entity Framework as it was too much for this small project. I ended up using the Dapper micro-ORM. Everything is static with some Javascript for the dynamic parts. The content is served statically to keep resource usage low. I also coded the SMTP server myself.

The web is fronted by nginx which act as a static file server and proxies dynamic requests to the Kestrel app server.

Unlike similar sites, my service runs well on mobile browsers and supports embedded pictures and file attachments.

You know, this is something that could be built as a "serverless" app for almost no cost using AWS services like SES, S3, Lambda, and DynamoDB. I'm sure that the VPS doesn't cost much, but it's a cost whether anyone is visiting the site or not.

Edit: Didn't mean to sound negative, so I hope it doesn't come across that way. Good job on building something! I've been struggling with that myself and these types of posts motivate me to just build something.