Big Free Casino

How it's built

The site is a Vite multi-page build, with one generated HTML page per game created from a single catalog file. Shared modules handle the wallet, stats, settings, sound and analytics, and a table kit built on three.js supplies felt, chips, cards, labels and the bottom button dock, so a new game is a pure rules engine plus a thin interface. Engines are plain JavaScript with node:test files, which is why they can be checked against published figures without a browser. The site is hosted on Cloudflare Pages. Pages Functions and a D1 database collect first-party analytics and keep the shared Caribbean Stud meter, and a service worker built at deploy time makes offline play possible. The balance itself lives in the player's browser.

Built with

• Vite
• three.js
• JavaScript
• Canvas 2D
• Cloudflare Pages
• Cloudflare Pages Functions
• Cloudflare D1
• Service worker
• node:test
• GA4

The hard parts

1. Two tabs, one wallet

   Two tabs changing the balance at nearly the same moment could each overwrite the other, because a write from one tab takes a moment to reach the other. We gave every wallet change an id and kept a short list of applied ids. When another tab's write arrives missing one of this tab's recent changes, the change is applied again on top of it, so both tabs end up with every stake and every return.

2. Analytics inside a free database limit

   The collector had to track every click and round without burning through the daily write limit of a D1 database shared with other client sites. The browser sends events in batches, every 30 seconds, at 40 events, or when the tab hides. The server checks and caps each batch, writes it in a handful of statements by unpacking JSON, and keeps a running estimate of the day's writes. As the day fills, it stops saving raw events first, then sessions.

3. Offline play without stale pages

   The service worker serves pages network first and falls back to the saved copy after four seconds, so players online always get the latest build. Each file carries a content hash, and a deploy re-downloads only the files that changed. A kill switch in the site config makes the next deploy delete every saved file and unregister the worker. Testing was its own trap: Playwright's offline switch breaks service workers in WebKit, so we tested there by shutting the server down instead.

4. Slot math and motion both measured

   Gold Vault's exact return is 95.962%, and a 100 million spin simulation measured 95.963%. Reel motion is written as tested functions of time: a wind-up, 17.5 cells per second, a hard stop with a 0.22-cell overshoot and a 0.15 second spring back. The timings were measured from free slot demos, then confirmed in Chromium, and the game held 60 frames per second on a phone profile slowed four times.