Documentation Index
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Proton VPN for Android supports several VPN protocols. The protocol controls how your device establishes and encrypts the VPN tunnel. Each option involves different trade-offs between speed, compatibility, and censorship resistance.
Smart protocol is recommended for most users. It automatically selects the best available protocol for your network without any manual configuration.
Available protocols
Smart
WireGuard
Stealth (WireGuard TLS)
ProTun
Smart protocol automatically tests and selects the best protocol for your current network conditions. It tries protocols in order of preference — starting with WireGuard UDP — and falls back to alternatives if a protocol is blocked or unavailable.How it works:
- Probes available ports and protocols at connection time
- Falls back through WireGuard UDP → WireGuard TCP → WireGuard TLS (Stealth) as needed
- Re-evaluates on each new connection
Smart protocol is the default and requires no manual intervention. Use it unless you have a specific reason to pin a particular protocol. WireGuard is a modern VPN protocol designed for simplicity and high performance. It uses state-of-the-art cryptography (ChaCha20, Poly1305, Curve25519) and has a significantly smaller code surface than older protocols.Proton VPN supports WireGuard with three transmission options:| Variant | Transport | Use case |
|---|
| WireGuard (UDP) | UDP | Default; fastest in most conditions |
| WireGuard TCP | TCP | Useful when UDP is blocked by a firewall |
| WireGuard TLS (Stealth) | TLS over TCP | Censorship resistance; disguises VPN traffic as regular HTTPS |
Stealth is Proton VPN’s name for WireGuard tunnelled over TLS. Because TLS traffic is indistinguishable from regular HTTPS, Stealth can bypass deep packet inspection (DPI) firewalls and VPN-blocking systems used in some networks and countries.When to use Stealth:
- You are in a country or on a network that actively blocks VPN connections
- Standard WireGuard and WireGuard TCP both fail to connect
- You need censorship resistance alongside end-to-end encryption
Stealth has slightly higher latency than plain WireGuard UDP because of the additional TLS encapsulation. Smart protocol will fall back to Stealth automatically when needed. ProTun (Proton Tunnel) is Proton VPN’s own WireGuard-based tunnelling layer. It uses the same underlying WireGuard cryptography but runs through Proton’s custom transport implementation. In API communications, ProTun is reported as WireGuard.ProTun is available in the protocol selector when enabled by a feature flag. Its behaviour mirrors WireGuard but uses an alternate network stack for improved stability in specific network environments.
Protocol comparison
| Protocol | Speed | Compatibility | Censorship resistance | Notes |
|---|
| Smart | Adapts automatically | Excellent | Yes (falls back to Stealth) | Recommended default |
| WireGuard (UDP) | Fastest | Good | Low | Best speed on open networks |
| WireGuard TCP | Good | Excellent | Moderate | Works through strict firewalls |
| Stealth (WireGuard TLS) | Good | Excellent | High | Use when VPN is blocked |
| ProTun | Good | Good | Moderate | Proton custom transport layer |
Changing the protocol
You can change the protocol globally in Settings, or override it per connection profile.
Global setting
Open Settings
Tap the Settings icon in the bottom navigation bar.
Select Protocol
Tap Protocol under the Connection section.
Choose a protocol
Select one of the available options. The change takes effect on your next connection.If you are currently connected, disconnect and reconnect for the new protocol to be used.
Per-profile override
Profiles can have their own protocol setting that overrides the global default. See Connection profiles for details.