One developer, one mechanic
The design is close to minimal: control one circle, eat anything smaller, avoid anything bigger, grow. There is no story, no progression system and nothing to install. It runs in a browser tab, which meant it could spread anywhere a school or office computer could open a web page.
That is the whole innovation and it was enough. VentureBeat, reviewing the field in February 2017, described a genre built on exactly these properties: tiny file sizes, immediate play, simple mechanics, competitive multiplayer and cultural resonance with internet humour.
Two weeks to a publisher
The speed is the part that still reads as implausible. Within a week of release every Miniclip employee was playing the game. The company then met Valadares in Lisbon and took the publishing rights — roughly two weeks after launch.
Distribution of that kind normally follows months of pitching. Here the product did the work: a game that spreads by link does not need a publisher to find an audience, it needs one to handle the servers, the app stores and the money once the audience has already arrived. A single developer cannot keep a global multiplayer game online by himself, and that is the problem Miniclip was buying.
PewDiePie and two billion views
The accelerant was YouTube. PewDiePie, then among the most-followed creators on the platform, made a viral series playing it, and VentureBeat identifies that as transformative for the game's popularity. By March 2016 the site reported Agar.io content had passed two billion views on YouTube.
That figure is the real measure of the phenomenon. The game was not merely played; it was watched, which is how a browser curiosity became a format that other developers copied within months. Watching a stranger lose a two-hour cell is entertainment in itself, and it converts viewers into players at no cost to the developer.
Diep.io and the genre
In July 2016 TouchArcade reported the arrival of Diep.io on the App Store, from the creator of Agar.io — a tank game built on the same principles of instant multiplayer and permanent risk.
By 2017 the .io suffix was a genre label. VentureBeat noted Slither.io drawing 86 million monthly visits and observed that the audience skewed to 18 to 24-year-olds and to markets without a strong console industry — Brazil, Russia and Turkey among them. The genre's centre of gravity sat where its first author did.
What is documented — and what is not
Documented: that Valadares is Brazilian, that he created Agar.io, that it launched in April 2015, that Miniclip acquired publishing rights within about two weeks after meeting him in Lisbon, that the game passed two billion YouTube views by March 2016, and that Diep.io followed in July 2016.
Not documented in the reporting used here: his age. Wikipedia states he was 19 when he built Agar.io, but the cited news coverage does not confirm it, so this page leaves it open. Also absent: his earnings, his current projects and any interview in these sources.
What is documented — and what is not
✓ Documented
- He is a Brazilian developer and the creator of Agar.io, released in April 2015.
- Miniclip staff were playing it within a week and the company took publishing rights within about two weeks, after meeting him in Lisbon.
- Agar.io content passed two billion YouTube views by March 2016.
- Diep.io, by the same creator, reached the App Store in July 2016.
? Unverified, disputed or wrong
- His age at the time he wrote Agar.io.
- His earnings from the game or the publishing deal.
- What he has worked on since 2016.
- Any interviews in his own words.
Questions people ask about Matheus Valadares
Who made Agar.io?
Matheus Valadares, a Brazilian developer working alone. The game was released in April 2015.
How old was he when he made it?
Wikipedia states he was 19, but the news coverage used here does not confirm it, so this page does not assert an age.
How did Miniclip get involved?
Within a week of launch its staff were playing the game. The company met Valadares in Lisbon and took the publishing rights roughly two weeks after release.
Why did Agar.io get so big?
It ran instantly in a browser with no download, it was simple enough to explain in one sentence, and a PewDiePie video series made it a spectator phenomenon.
What is Diep.io?
His follow-up game, a tank-based multiplayer title that reached the App Store in July 2016.
What are .io games?
Browser-based multiplayer games with tiny file sizes and instant play. VentureBeat traced the category to Agar.io and noted Slither.io reaching 86 million monthly visits.
How much did he earn?
No figure appears in the sources used here.
Where is Matheus Valadares now?
The reporting used here ends in 2017 and does not say.
Quick quiz: how well do you know Valadares’s story?
When was Agar.io released?
How quickly did Miniclip take the publishing rights?
What was his follow-up game?
Sources
- The surprising momentum behind games like Agar.io — VentureBeat, 2017-02-11
- Darwinian bacteria survival game Agar.io has bagged 2B views on YouTube — VentureBeat, 2016-03-03
- Diep.io Hits the App Store From the Creator of Agar.io — TouchArcade, 2016-07-21
Checked by the Geniuses.club editorial team. Ages are given as of September 2026.
