how it works
Every page on either.fm is a single decision: two songs, diagonally split. You pick one. We record it. The next pair shows up. After about a hundred picks you've made enough decisions for an honest top 10 to surface.
The screen is one image cut by a slash. Each half is one song.
Tap, click, or press A / B / arrow
keys. Don't know either? Press S or the skip pill —
you don't owe the algorithm a guess.
A league is a finite catalog. Today: 91 Taylor Swift songs, 19 ABBA tracks, a 7-step walkthrough that teaches the controls. Every league is self-contained — votes in one don't bleed into another.
Behind the scenes, each item carries an Elo number that rises when it wins a duel and falls when it loses. The size of the change depends on whether the win was expected. Beat a higher-ranked song and your number jumps; beat a lower-ranked one and it barely moves.
The Elo math is the boring part. If you want to read about it anyway: the nerd alert article on Elo.
We save your votes locally first, then sync to the server when you sign in. /me is where your per-league top 10 lives — the songs you ranked highest, with vote counts, alongside the live community ranking for comparison.
Recommend songs. Predict what you'll like. Promote items based on partner deals. Reorder rankings to keep you scrolling. Track you across the web. The whole point of pairwise is that you reveal your taste through choices, not surveys; we'd be undoing the math by trying to game it.
Either is the choice between two things — and a well-trodden pronunciation argument. fm is the radio-dial slot where music lives. The slash is the choice itself, frozen. More on the pronunciation thing.
One day, yes — opening up league creation is on the list. Right now we're busy building, so the catalog stays editorial while we get the format right. If you've got a brand or a band that wants one sooner, sponsored leagues are how — see /sponsor.
Yes, constantly. Rankings respond to live votes. Today's #4 might be next week's #1.