Why Protocol Choice Matters
The VPN protocol determines how your device establishes and maintains the encrypted tunnel. Different protocols make different trade-offs between speed, security, battery life, and compatibility. Most VPN apps select automatically, but knowing the options lets you override that choice when it matters.
OpenVPN
OpenVPN is the long-standing standard. It uses SSL/TLS encryption, works over both TCP and UDP, and is battle-tested. The downside is speed: OpenVPN runs in user space rather than the kernel, adding latency. It is also harder to set up manually. Most VPN providers still include it for compatibility with older devices and firewall-heavy networks.
WireGuard
WireGuard is the modern alternative. It runs in the kernel, uses state-of-the-art cryptography (ChaCha20, Curve25519), and has a codebase roughly 70 times smaller than OpenVPN. The result is faster connection times, better throughput, and lower battery drain on mobile. Most major VPN providers have added WireGuard support in the past two years. If your VPN offers it, use it.
IKEv2/IPSec
IKEv2 is particularly good on mobile because it reconnects quickly when you switch between Wi-Fi and cellular. Battery impact is lower than OpenVPN. It is the default protocol on many iOS VPN apps for this reason. Security is strong when implemented correctly, though it has a history of being blocked more easily by some firewalls than WireGuard.
Which to Pick
For daily use on desktop or mobile: WireGuard. For networks that block modern protocols: OpenVPN over TCP on port 443. For iOS and frequent network switching: IKEv2. For maximum privacy on a slow connection: OpenVPN with AES-256 and no speed concerns.