Port Zero docs

Set every port to 0 and start your program. Port Zero gives it a stable domain instead — no port to remember, no EADDRINUSE. These pages cover the free, local overlay and the paid Cloud tunnels product.

Start here

Install Port Zero, tag a process or container, and see a stable URL.

  • Getting started — Install Port Zero, tag a process or container, and open a stable URL.
  • Tunnels & PZ_TUNNEL — The full-domain rule, template variables, and companion environment variables.
  • Examples — Minimal, ready-to-run PZ_TUNNEL examples in several languages.
  • How it works — What the background daemon does when PZ_TUNNEL is set, for Local and Cloud tunnels.

Cloud tunnels

Share a tunnel with reviewers and teammates over the internet.

  • Cloud tunnels — Reach a local process from the internet, read tunnel status from scripts and CI, and understand the local view vs. the dashboard.
  • Review apps — Build per-PR preview environments on top of Port Zero tunnel names — no orchestrator required.
  • Review records — Tie reviewer feedback pinned on a tunneled app to the commit that fixes it.
  • CI & agent credentials — Let CI jobs and coding agents mint short-lived, team-scoped Cloud tunnel credentials — no long-lived tokens to store.
  • Teams & invitations — Invite teammates by email — they do not need an account first — and manage who is on your team.

AI agents

Let a coding agent drive Port Zero directly.

Reference & safety

What the daemon can see, what needs elevated privileges, and how to fix common problems.

  • Security model — What the daemon reads, what it sends, why it needs elevated privileges, and how the local certificate authority is constrained.
  • Platform privileges — What the Local overlay needs elevated privileges for, per platform, and what happens without them.
  • Troubleshooting — Fixes for the most common Port Zero problems.
  • Known limitations — Specific, identified gaps in local certificate-authority trust, and the documented fallback for each.
  • FAQ — Frequently asked questions about Port Zero's design decisions and remote coding-agent setup.
  • Port Zero vs. ngrok — How Port Zero's flat-rate tunnels and local port-conflict fix compare to ngrok's metered model. Public facts as of July 2026 — verify current ngrok terms at ngrok.com.