What happened to Slither.io?

Slither.io (2016) remains playable but server populations are fragmented. The original site (slither.io) is still operational. Latency above 80ms round trip — common from Asia or South America to US servers — makes the tail-cutting mechanic unreliable. It is still the best introduction to the genre for players who haven't tried it.

Are .io games safe for children?

Skribbl.io and Gartic Phone are appropriate for supervised children with custom word lists. Most other .io games have either player chat (Agar.io, Krunker.io) or mild violence (Surviv.io, Diep.io) that parents should evaluate before extended play.

The Five .io Games Still Worth Your Fifteen Minutes

The .io genre peaked sometime around 2018. Server populations fragmented, clones diluted the market, and every interesting mechanic was either absorbed by a major platform or left to run on servers that had stopped being maintained. But five titles have held on for specific reasons that are worth understanding.

Skribbl.io — the one that works at any age

Skribbl.io (2016, Timo Becker) is a browser multiplayer drawing-guessing game with no violence, no required account, and a word list that can be customised per private lobby. Bramwell has used it with school groups aged seven to seventeen and with corporate teams aged twenty-five to fifty-five. The core mechanic is accessible enough that a child who has never played a browser game can participate. The private lobby system with custom word lists turns it into a genuinely flexible party game tool. Server populations remain healthy in Europe and North America as of 2025. Load time: six seconds on a 4G connection.

Krunker.io — the one that aged into a real competitive game

Krunker.io launched in 2018 as a Wolfenstein-style first-person shooter with low-poly graphics and immediate play. By 2021 it had a ranked ladder, a custom map workshop, tradeable weapon skins, and competitive tournaments. By 2024 it had migrated significant portions of its codebase to client-server tick rates that would not embarrass a conventional PC shooter. It is the most convincing argument that serious competitive gaming can exist in a browser tab. Required account for ranked play; anonymous play available for casual matches. Not appropriate for children.

Agar.io — the original, still running

Agar.io (2015, Matheus Valadares) invented the genre. You are a cell consuming smaller cells and avoiding larger ones. The mechanic takes twenty seconds to learn and has a depth ceiling measured in years of professional play. The official servers have declined in population since 2020, but unofficial server communities maintain private lobbies. The game is included here not because it is the best .io game on the list but because understanding it is prerequisite to understanding everything that came after it. Play it once to understand why it worked.

Gartic Phone — what Skribbl became for creative players

Gartic Phone (2020, Onrizon) extends the drawing-guessing mechanic into a telephone-game chain: you draw something, someone else captions it, someone draws that caption, someone else captions that drawing. By the tenth step, a drawing of a dog has become a philosophical treatise on mortality. It is funnier than it sounds in description and requires less artistic skill than it appears to demand. Works well with groups of six to twelve. Account creation optional. Load time under ten seconds.

Surviv.io — what the battle royale genre looks like without a download

Surviv.io (2017) applies the battle royale template to 2D top-down gameplay. No installs, no queues, no required account. Matches last four to twelve minutes. Server populations have declined significantly since 2020 but are sufficient for regular matchmaking in North American and European time zones. It is mentioned here specifically as the answer to 'is there a battle royale game I can play in a browser during lunch?' The answer is yes, and it is this game, and it has held up.