The "click a link, play" experience looks like magic from the outside: no download, no install, no updates. So how does a browser game actually work? Using SargasmGames as the example, let's look under the hood for the technically curious.
HTML5 Canvas: the game's easel
Our games are drawn on an HTML5 Canvas — the standard way of telling the browser "give me an area I can paint pixels on". The game loop runs ~60 times per second: each frame first updates the world (objects move, collisions resolve), then redraws the scene. The difference from phone games is that this loop is driven by the browser's requestAnimationFrame scheduler rather than the operating system.
Why does it load so fast?
Each of our games is a single HTML file: code, styles and art live in one file. Instead of huge texture packs, all visuals are drawn at runtime with the Canvas API — flowerpots, characters and corridors included. That's why an entire game is smaller than a single photo on most news sites and opens in seconds.
Security: the sandboxed iframe
Games don't load directly into the page; they run inside a sandboxed iframe. The sandbox is a security fence limiting what a game can do: it can't reach outside its box, and it can't touch your account or cookies. Its only channel to the platform is messaging (postMessage): the game says "here's my score", the platform verifies and records it. This separation protects both you and the fairness of the leaderboards.
The journey of a score
When a run ends, the score isn't written straight to the board. It's first signed with a per-session token, then passes plausibility checks on the server: scores impossible for the play duration, resubmissions and suspicious patterns are filtered out. Every row you see on a leaderboard has passed through that sieve.
Checkpoint architecture: continue where you left off
For the "continue" feature, the game entrusts a small snapshot of its state (wave, lives, score) to the platform at key moments. When you die, the platform asks: do you have a continue available? If a membership allowance or coins confirm it, the game receives its snapshot back and teleports you there. The important detail: the platform, not the game, validates the continue condition — no game can hand out free continues on its own.
Why the browser instead of an app?
Short answer: friction. The decision to install a mobile game is made in seconds, and "no storage left" wins often. For a browser game the decision is one click. A single codebase also runs on phone, tablet and desktop simultaneously — we test on all three before releasing.
Send technical questions via the contact page; we may answer the interesting ones in future posts. 🛠️