Planned Release Date: Q3 2026

About This Software

You found a great co-op game, and it only does local multiplayer. Same network, no online option, so the friend across the country is out of luck. Porthole makes that friend show up as if they were on your local network, so you can play together over the internet.

What is Porthole?

Porthole is a lightweight desktop utility that lets you share a local TCP or UDP port with your Steam friends over Steam's own network. They connect to your server (or any local service) as if it were running on their own machine - with no port forwarding, no public IP, and no router setup.

It's a networking utility, not a full VPN: Porthole shares the specific ports you choose, not your whole network.

Typical uses

• Play local-multiplayer and LAN games with friends who aren't on your network.

• Host a game server for your friends.

• Share any local TCP or UDP service with people you trust.

How it works

1. Pick the local ports to share (or auto-detect them from a running game) and create a lobby.

2. Friends join with a short share code, from your Steam friends list, or by Steam ID.

3. You offer each port; they approve it and it binds on their own machine.

4. Traffic tunnels through Steam's peer-to-peer network, automatically falling back to Valve's relay if a direct connection isn't possible.

Key features

• Works with both TCP and UDP servers.

• Built-in port detection - find the ports a running game or app is using ao lookup needed.

• No port forwarding and no public IP - works behind NAT and CGNAT.

• Join by share code, from the Steam friends list, or by Steam ID.

• Optional password-protected lobbies.

• Per-port approval, local remapping, and host kick/ban controls.

• Direct peer-to-peer with automatic Valve relay fallback.

• Adaptive rate control tuned for the Steam relay.

• Clean native GUI that runs from the system tray, plus a scriptable command-line interface

• Windows and Linux/SteamOS support.

Pick a port, share a code, and play.

AI Generated Content Disclosure

The developers describe how their game uses AI Generated Content like this:

Generative AI tools were used during development, including for localization of in-game text.