How to Fix a Web Game That Won't Load on itch.io

A game that runs locally but hangs on itch.io is usually missing the SharedArrayBuffer headers itch can provide via a checkbox, or has the wrong file structure. Here is the fix.

How to fix it

1. Enable SharedArrayBuffer support

In the itch.io project's HTML settings, tick the SharedArrayBuffer support option. This makes itch serve the cross-origin isolation headers threaded engines (like Godot and some Unity builds) require.

2. Get the zip structure right

The uploaded zip must have index.html at its top level, not inside a subfolder. itch loads index.html from the root; a nested structure shows nothing.

3. Read the console error

If it still fails, open developer tools on the game page. The console names the specific cause — a missing file, a header error, or an unsupported feature — so you fix the right thing.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every HTML5 error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.