Pastel might be a bit more popular than OpenSMTPD. We know about 2 links to it since March 2021 and only 2 links to OpenSMTPD. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
I've had something of the same experience with Postfix, u/0x29aNull. Check out OpenSMTPD. It is lightweight and standards compliant. I know that there are packages for Debian and Alpine Linux. There may also be ones for Fedora/RHEL derivatives. I use it in my environment on OpenBSD. Source: about 1 year ago
When I installed Rspamd with on OpenBSD / OpenSMTPD the other day, DKIMProxy out (dkimproxy_out daemon), which had been got via OpenBSD Ports package system, was used to add DKIM signatures to mails in order to improve security on emails. - Source: dev.to / almost 3 years ago
Competitors There are a few competitors out there that do something very similar (see https://ruttl.com/, https://usepastel.com/, https://bugherd.com/, https://www.markup.io/). This seems to suggest that there seems to be a general market for such a product. Source: about 1 year ago
Yes, we used Pastel https://usepastel.com and it was very nice overall. - Source: Hacker News / almost 2 years ago
Postfix - Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail.
Iterate - Get the feedback you need to build better products
sSMTP - sSMTP is a simple MTA to deliver mail from a computer to a mail server.
BugHerd - BugHerd: The Website Feedback Tool for Agencies
Exim - Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet.
Usersnap - Usersnap is a customer feedback software for SaaS companies that need to constantly improve and grow their products.