Surely a custom vibe-coded mess of a web frontend for ImageMagick (it allows uploading a whole lot of scanned images, then presents a comfy web UI which allows choosing particular transformations - posterize to bilevel, trim, straighten, deskew, scale-to-page-size-and-add-edges). It runs in an ancient discarded-and-salvaged laptop.

I also use the same laptop as:

• Livekit SFU (transporting media for Element (Matrix) calls)
• STUN/TURN server (transporting media for Snikket (XMPP) calls)
• email server (Postfix)
• hosting a QR scanner webpage, so I could scan QRs in PCs with minimal fuss
• and of course, since it’s already there, home router (it’s in the basement, so too far to do WiFi. The WiFi access point runs in dumb bridge mode)

I also run a periodic HLS video broadcast (my home internet connection should survive something like 40 simultaneous watchers, I should figure out how to distribute it efficiently to other hosts). It’s too heavy for the ancient laptop, but (as it turns out, I measured yesterday), a NAS with a 4-core Intel N100 CPU just barely manages. I might switch to it, it’s probably more power efficient than the current desktop workstation.