Why only Spotify?
The box needs three things from a music service.
Control over playback, a way to stream to a speaker, and the album art. Spotify is the only big service that offers all three to a small home-made box.
1. Playback control
When you stand a photo on the easel, the box reads a link from the tag, something like spotify:album:…, and has to start that exact album by itself, with no phone involved. Lifting the photo has to pause it, and putting it back has to resume.
Spotify's public Web API allows exactly this. Once you've signed the box in, it can say "play this album there", pause, skip and change the volume. Most other services only let you control playback from inside their own apps.
Spotify only allows playback control through its API on Premium accounts, so the box needs Premium.
2. Streaming to a speaker
The music has to come out of a real speaker. Spotify Connect lets the box send the album to any Connect speaker in your home.
The box can also be the speaker. It runs Raspotify, an open-source Connect receiver, and plays to a Bluetooth speaker you pair with it. In the Spotify app it shows up as Spotifactory, like any other speaker.
3. Album art
The photos are the whole idea, so the box needs the cover. When you choose Print Album, it asks Spotify what's playing, gets the cover art, prints it on Instax film and writes that album's link to the tag. The same information fills the now-playing screen.
The other services
Here's how the main alternatives compare on those three needs, as of October 2026. Services change their rules, so treat this as a snapshot.
| Service | Playback control | Streaming to a speaker | Album art |
|---|---|---|---|
| Spotify | Yes Web API | Yes Spotify Connect | Yes Web API |
| Apple Music | No Only from Apple's own apps | Phone only AirPlay from your iPhone | Yes Public catalogue search |
| YouTube Music | Unofficial No public API | Unofficial Community tools only | Unofficial No public API |
| Tidal | No No public playback API | Partners only Tidal Connect is for hardware makers | Yes Developer catalogue API |
| Amazon Music | No No public API | Echo only Alexa devices | No No public API |
"Unofficial" matters more than it sounds. A Spotifactory is meant to sit on a shelf for years and just work, often in someone else's house. Tools that could break with any update, or get an account flagged, aren't a good fit.
If another service opens up all three, the box can learn it.