How I ranked the Lemmy instance visibility by sort type

I’m building Stakswipe, a mobile Lemmy client with a swipe-to-vote UI. One of the problems I ran into was the anonymous feed — when you’re not logged in, you need to pick an instance to connect to upfront, and that choice matters more than most people realise. Rather than just guessing or defaulting to lemmy.world, I wanted to objectively measure which instances give the best view of lemmy for someone browsing without an account. I put together a benchmarking script that tests the top 20 instances by monthly active users and scores them.

It’s worth noting that some instances defederate from others or block certain communities, and that’s completely fine — it’s one of Lemmy’s strengths. Communities and instances should be able to self-govern and set their own norms. These rankings aren’t a judgment on any instance’s moderation choices; they’re purely about federation breadth and visibility of all that lemmy has to offer for a general anonymous feed.

What I measured

For each instance × sort combination, I fetched posts anonymously until I hit a quality floor suited to that sort’s algorithm:

• Active (48 hours) — Lemmy’s Active sort decays based on the most recent comment time, capped at 48 hours. The script stops when the last post on a page has been quiet for more than two days.
• Hot (24 hours) — Hot decays based on post publication time using a gravity of 1.8. Anything older than a day is well past its peak rank.
• New (2 hours) — Purely chronological. I stop at 2 hours to focus on live traffic.
• Top 6 Hour / 12 Hour / Day — These are ranked by score within a fixed server-side time window, so the feed exhausts naturally. I stop when posts drop below 5, 10, and 20 absolute votes respectively.

How scoring works

Every post has a canonical ActivityPub ID (ap_id). The script builds a universe — the union of all unique posts seen across all instances for a given sort. An instance’s ability to surface that universe is what is measured.

Each instance is scored across four metrics, then the scores are normalized against the best performer and combined:

Metric	Weight	What it captures
Posts visible	40%	Federation breadth — how much of the universe this instance sees
Comments visible	35%	Federation depth — whether post threads actually federate
Post vote totals	15%	Signal quality — are the votes syncing, or just stubs?
Comment vote totals	10%	Thread engagement fidelity

The instances with the highest weighted score for each sort type are shown.