Prosody (XMPP server). Setup takes an hour at most even if you have never worked with Lua. Easy to interact with (it has a built-in shell), easy on system resources, and easy-to-understand config. Support for groups, E2EE, attachments including videos and voice recordings, among others.

This, and don’t forget to use W3’s HTML and CSS validators.

I used nsupdate for years and it worked just fine. I remember it being down, one time only, for like five minutes. For a project that depends entirely on donations, the service and availability they provide are just awesome.

This, coupled with the fact that firewalls are protocol-agnostic. You can, for instance, use ‘port https’ in your Packet Filter config instead of ‘port 443’, but that simply means that PF will block/pass traffic to whatever service is bound to that particular port, and NOT https connections in general.

The fact that I bought all my machines used (and mostly on sale), and that not one of them is general purpose, id est, I bought each piece of hardware with a (more or less) concrete idea of what would be its use case. For example, my machine acting as a file server is way bigger and faster than my desktop, and I have a 20-year-old machine with very modest specs whose only purpose is being a dumb client for all the bigger servers. I develop programs in one machine and surf the internet and watch videos on the other. I have no use case for VMs besides the Logical Domains I setup in one of my SPARC hosts.

Fossil

Came into the thread just to say this. Very happy and thankful you mentioned it already. I think fossil is THE underrated vcs.

I’d like to mention https://chiselapp.com/, since OP’s wish is, AFAICT, to have a service that’s hosted elsewhere.

Er. ‘I am done with Google’. Watch the video on YouTube…