FAQ

This page grows from real questions people actually ask, not speculation.

Where do I start? How Foldback Works for the pieces and what each one does; the Quickstart for the smallest real integration. Not yet on crates.io — depend on it as a git or path dependency in the meantime.

Why xxHash3 and not a cryptographic hash? This is integrity-checking (did two peers compute the same state), not security — a non-cryptographic hash is faster and that’s the only property that matters here. See the performance spike for why speed was worth validating rather than assuming.

Does Foldback slow down my game? The validated hot-path cost (hash + ring-buffer handoff) is under 200µs even at 100,000 simulated entities — well under 1.2% of a 60Hz frame budget. See Performance for the full numbers.

Why is field-hashing opt-in instead of opt-out? So a newly-added non-deterministic field (a timestamp, a debug label) can never silently become a phantom divergence source. See RFC-0003.

Can I use this with Unity/Godot/Unreal? Yes to all three — see their integration pages: Unity, Godot, Unreal. Each has reflective hashing (see Auto/Reflective Hashing), and Unreal also has a Mass Entity integration.