Many people confuse V2Ray and Xray. In short, they are two branches of the same tree.
The backstory
V2Ray is maintained by the v2fly community; the code is v2ray-core. In 2020 some developers spun off Project X and produced Xray-core. Think of one as upstream and the other as a more aggressive, active fork.
Key differences
- Update pace: Xray iterates faster.
- Exclusive features: REALITY, XTLS Vision and some uTLS fingerprint disguises exist only in Xray.
- Style: v2ray-core is comparatively conservative and stable.
Compatibility
Base protocols — VMess, VLESS, Trojan, Shadowsocks — interoperate between the two, and the config formats are very similar, so porting between them takes little change.
How to choose
For REALITY or the newest features, pick Xray — most clients now bundle Xray by default. v2rayN lets you switch cores in settings, and you can even install both and switch as needed.
If you set up REALITY or
flow=xtls-rprx-vision and can't connect, the first thing to check is that both server and client run Xray, not v2ray-core.