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Technical requirements

Your game must run smoothly on a wide range of browsers and devices. The numbers below are defaults — exceptions may be granted, but you should design to these targets.

File size and loading​

LimitValue
Total build size≤ 250 MB
File count≤ 1,500 files
Initial download≤ 50 MB
Initial download (mobile homepage eligibility)≤ 20 MB
Time to first interactive frame≤ 20 seconds on broadband
Optimize aggressively

The smaller your initial download, the higher your play-through rate. See the optimization guide for engine-specific tips.

Paths​

  • Use relative paths when referencing assets inside your game bundle.
  • Do not hot-link assets from external CDNs (Google Fonts, jsDelivr, etc.). Bundle everything.
  • Exceptions: multiplayer game servers and analytics services pre-approved during review.

Browsers and devices​

Desktop​

  • Chrome and Edge: must run smoothly at 60 fps.
  • Safari: support expected — non-compatible games may be hidden from Safari traffic.
  • Chromebooks: must run on devices with 4 GB RAM.

Mobile​

  • Must support touch input.
  • Games should accept keyboard and mouse input on desktop even if designed for touch.
  • Landscape is recommended; portrait is allowed with letterboxing on desktop.
  • iOS Unity WebGL games are disabled by default due to memory crash risks. They are re-enabled after enough successful play volume.

Aspect ratio​

  • Target 16:9 (e.g., 1280×720, 1920×1080) and scale to fill the canvas.
  • Reference resolutions: 640×360, 836×470, 1031×580.

Performance​

  • Hold a stable 60 fps during active gameplay on mid-range hardware.
  • Avoid memory leaks — long sessions (> 30 min) should not degrade performance.
  • Tab visibility: pause heavy work (requestAnimationFrame, audio) when document.hidden is true.

Security and privacy​

  • Do not collect personally identifiable information without explicit consent.
  • All third-party scripts must be pre-approved.
  • Privacy notices must be non-blocking — they cannot prevent gameplay.

Storage​

  • Wrap localStorage access in try/catch for incognito-mode browsers that throw.
  • Maximum 1 MB of save data per game (see Data SDK).
  • Prefix keys you do not want to sync to the cloud with funox_ignore_.

Quick reference​

Text7 lines
1build size          ≤ 250 MB2file count          ≤ 15003initial download    ≤ 50 MB (≤ 20 MB for mobile featured)4time to play        ≤ 20 s5aspect ratio        16:9 (responsive)6target fps          607mobile RAM target   4 GB
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