Port 3030: Unassigned — Feathers.js's Quiet Default

What This Port Is

Port 3030 sits in the registered ports range (1024–49151). These ports are managed by IANA, which assigns them to specific services after application. Port 3030 has never been assigned. It's available, and the squatters have moved in.

Who's Actually Using It

Feathers.js is the primary occupant. Feathers is a Node.js framework for building real-time APIs and REST services — it scaffolds new projects with this in config/default.json:

{
  "host": "localhost",
  "port": 3030
}

Every developer who generates a Feathers app and types npm start gets a server at http://localhost:3030. The framework made no formal claim to the port through IANA — it just chose 3030, shipped it as the default, and now the community treats it as Feathers territory.¹

NetPanzer also uses this port. NetPanzer is an open-source multiplayer tactical tank game, originally developed by Pyrosoft Inc. in the late 1990s and released under the GPL in 2002. Game servers listen on port 3030 for client connections on both TCP and UDP.²

Beyond these two, 3030 occasionally shows up as a general-purpose development port for Node.js applications — not because anything specifies it, but because 3000 is React's territory, 3001 feels redundant, and 3030 has a pleasing symmetry.

How to Check What's Listening

# macOS / Linux
lsof -i :3030

# Linux (alternative)
ss -tlnp | grep 3030

# Windows
netstat -ano | findstr :3030

If you see a process on this port and you didn't start anything, check whether a Feathers development server was left running.

Why Unassigned Ports Matter

The registered port range exists to prevent collisions — two services accidentally fighting over the same port. IANA assignment is how that coordination happens. But IANA assignment requires an application process that most projects skip.

The result is a large number of ports that are officially empty but practically occupied. Port 3030 is a mild example: the collision risk is low because Feathers.js is primarily a development-time default, not a production service. But on a machine running multiple Node.js projects, two Feathers apps will absolutely fight over it.

This is why development frameworks increasingly let you configure the port, or randomize it, rather than locking in a default. The registry has gaps. Projects fill them informally. Collisions happen.