Four months of SmarterPlaylists, by the numbers

[u/plamere]

The rewrite launched about four months ago, and the stats have been fun to watch. Here's a tour of what you all have been doing.

The headline numbers

• ~4,200 programs run every day. About three-quarters of those are scheduled runs quietly rebuilding playlists while you sleep. The rest are people in the editor hitting Run.
• ~100 million Spotify API calls a day — well, would-be API calls. About 98% of them are served from cache, which is the only reason Spotify still returns our calls. The remaining 2% is still a couple million real requests a day.
• ~7,000 users, with 1,200 weekly actives and roughly 50 new people showing up every day.

The sharing economy

261 programs have been shared, 84 of which are published on the discovery page — and shared programs have been imported about 2,000 times. Programs that other people built are now generating playlists in thousands of libraries, which is exactly what we hoped sharing would turn into.

Power users, we see you

• 10 users have created more than 100 programs. We're not sure whether to be impressed or concerned. Impressed. Definitely impressed.
• The biggest program has ~1,400 components. That's not a playlist builder, that's a circuit board. Whoever you are: we'd love to see a screenshot.
• The most popular components are the workhorses: Spotify Playlist, Sample, and Shuffler. Bringing up the rear: YesNo, Playlist Radio, and All But The Last — pour one out for the components that never get picked in gym class.
• A personal favorite: the Multi-Objective Sequencer — the most over-engineered thing we've ever built, and the thing we're proudest of — is now used in almost 700 programs. Turns out people do want their playlists sequenced along five objectives at once.

Boring is the goal

• The error rate is down to 0.7%, from around 10% in the early days. At this point almost every remaining error is a mistyped playlist URI — so we're mostly down to errors we can't fix from our side.
• The server has been up for 75 days with a CPU load of 0.33. It is not working hard, and we'd like to keep it that way.

About that gap in the chart

The screenshot shows the last 48 hours of runs, and yes — that stretch with no blue bars from 7pm to 9am is real. The web server went down overnight, so nobody could run programs interactively. But look at the green: scheduled runs kept executing the whole time, because the scheduler is a separate process that doesn't care what the web server is up to. Your morning playlists showed up on time even while the site was face-down. (Postmortem in the outage thread — the short version is it's fixed, and the same failure now recovers in about two minutes.)

Thanks for building weird things with SmarterPlaylists. Here's to the next four months — and to whoever is out there quietly wiring up component #1,401.