How to Fix a Web Game Losing Saves When the Browser Evicts Storage

Players return after a few weeks and their progress is gone. The browser reclaimed your best-effort storage to free space. Requesting persistent storage tells it not to, protecting saves from eviction.

How to fix it

1. Request persistence

Call navigator.storage.persist() (ideally after the player has invested some time) to mark your origin's storage as persistent so it survives eviction sweeps.

2. Check the quota and usage

Use navigator.storage.estimate() to watch how close you are to the quota and warn or prune before the browser decides for you.

3. Offer export and cloud sync

Provide a manual save export and, if you have accounts, a server-side sync so a lost local store is never the only copy of progress.

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.