













MooMoo.io is a top-down survival and base-building game created by Sidney de Vries — the Swiss developer who would later make Krunker.io. It arrived in 2017 and established a template that the whole survival corner of the .io genre still follows: gather resources by hand, spend them on structures and upgrades, and defend what you built against players who would rather take it than make their own.
The economy runs on windmills. Wood and stone come from chopping trees and mining rocks, and those resources buy walls, spikes, traps and — crucially — windmills, which generate points continuously for as long as they remain standing. Points are the score, so a player with a well-defended cluster of windmills accumulates a lead simply by existing. That single mechanic converts base-building from a defensive chore into the primary way you win, and it is why MooMoo bases are worth attacking.
The age system provides the progression. As you accumulate points you advance through ages, and each age unlocks new buildings, weapons and hats. Hats are more important than they sound: they are equipment slots with real effects, granting bonuses to damage, movement, resource gathering or defence. Choosing the right hat for what you are currently doing — farming, raiding, or defending — is a genuine tactical decision, and swapping between them mid-fight is standard high-level play.
Combat is deliberately crude, and that crudeness shapes everything. You swing a melee weapon in an arc, so fights are about spacing and timing rather than aim. Spikes placed around a base damage anyone who touches them, meaning a well-designed base fights for you. The classic raiding technique is to wall an opponent in — trapping them inside their own structures so they cannot escape while you dismantle everything around them.
There is a day-night cycle, and nights are dangerous. Visibility drops, and the game becomes considerably more hostile for anyone caught away from their base without preparation. Experienced players treat the cycle as a schedule: gather in daylight, fortify before dark, and raid when others are least able to respond.
MooMoo.io is best on desktop, where the keyboard shortcuts for switching buildings and hats make a real difference, though it is playable on touchscreens with on-screen controls. It runs entirely in a browser with no download, and there is no account requirement — everything you build exists only for the length of your session, which is part of what makes losing a base sting.