Serving the For You Feed

· databases · Source ↗

TLDR

  • A single Go process on a home gaming PC serves Bluesky’s For You Feed to 72,000 users for $30/month.

Key Takeaways

  • The feed runs on one Go process backed by SQLite on a 16-core, 96GB RAM, 4TB NVMe home PC in spacecowboy’s living room.
  • Recommendations use collaborative filtering on likes: find what others who liked the same posts as you are liking.
  • SQLite stores 90 days of relevant firehose data, currently consuming 419GB.
  • Public traffic hits a $7/month OVH VPS, which proxies to the home server over Tailscale.
  • Total monthly cost: $20 electricity + $7 VPS + $3 domains = $30/month.

Why It Matters

  • The Bluesky AT Protocol lets anyone publish a custom feed algorithm, bypassing centralized recommendation control entirely.
  • This architecture scales to Bluesky’s full ~1 million daily active users on current hardware with a cheaper algorithm, per spacecowboy’s own estimate.
  • A $30/month home-lab stack serving 72,000 users challenges assumptions about infrastructure cost for social recommendation systems.

Simon Willison’s Weblog · 2026-04-24 · Read the original

Related coverage