Generic VPN protocols have characteristic handshakes. State-grade firewalls can fingerprint them in milliseconds. REALITY removes the fingerprint by piggy-backing on a real TLS handshake to a non-VPN destination.
How it works
When you connect, the client opens a TLS handshake that looks identical to one for a normal HTTPS website (e.g. a major CDN). Mid-handshake, a side channel signals the server to redirect into the VPN tunnel. To a passive observer, the entire exchange looks like a regular HTTPS request.
Why other VPNs don't have this
Most VPNs prioritise speed over censorship resistance. REALITY costs a few milliseconds at handshake time, which doesn't matter for a long-lived tunnel but does matter for ad-hoc benchmarks. We made the trade-off explicitly the other way.
When it's active
The app picks REALITY automatically when it detects DPI on the path. You can force it in Settings → Connection → Protocol → REALITY if you want to test.