Remote & Cloud Workspace Inspection

Traditional remote development extensions spawn multi-process Node.js environments and background indexers that consume 1 GB or more of server RAM.

px0 runs as an ultra-light single binary requiring strictly ~20-30 MB of host memory and boots in under 1 ms. The rendering workload is offloaded to your local browser tab (~80-150 MB), so remote devboxes and containers stay lean and responsive.

Network Topology

[ Remote Host / VM / Devbox ]                [ Local Machine ]
+---------------------------+                +-------------------------+
| px0 Server (:7777)        | <== Secure ==  | Local Web Browser       |
| (~20-30 MB host RSS)      |     Tunnel     | (~80-150 MB client tab) |
+---------------------------+                +-------------------------+

Pattern 1: Tailscale / WireGuard Mesh (Recommended)

When your remote machine is part of a private mesh network (such as Tailscale or WireGuard), px0 can bind directly to the machine’s private network interface:

# On remote machine: bind to all interfaces in headless mode
px0 -host 0.0.0.0 -port 7777 -no-open /path/to/remote/code

Then open the machine’s private IP or MagicDNS hostname in your local browser:

http://100.x.y.z:7777

Opening px0 directly by private IP allows both fast code navigation and authenticated agent editing.

Pattern 2: SSH Port Forwarding

If you access your server through standard SSH, forward the px0 port over your existing encrypted SSH connection:

# Connect with port 7777 forwarded to your local machine
ssh -L 7777:127.0.0.1:7777 user@remote-server.com

Once connected to the remote shell, start px0 binding to localhost:

px0 -no-open /path/to/remote/code

Open your local browser to http://127.0.0.1:7777. All traffic is forwarded securely through your SSH tunnel.

Pattern 3: Reverse Proxy or Tunnels

For persistent or shared inspection endpoints behind Nginx or Cloudflare Tunnels:

px0 -host 127.0.0.1 -port 7777 -no-open /workspace

Example Nginx reverse proxy configuration block:

server {
    listen 443 ssl http2;
    server_name inspect.internal.domain;

    location / {
        proxy_pass http://127.0.0.1:7777;
        proxy_http_version 1.1;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_buffering off;
    }
}

Pattern 4: Reverse Proxy & Subpath Hosting (-base-path)

When hosting px0 behind an API gateway, ingress controller, or multi-tenant review platform (such as PR review pods at https://tenant.px0.ai/rev-123/ or internal portals at https://corp.internal/tools/px0/), px0 can be served from a URL subpath rather than the root domain:

px0 -base-path /rev-123/ -host 0.0.0.0 -port 7777 ~/workspace

Key capabilities:

• Endpoint Prefixing: Automatically prefixes all HTTP multiplexer endpoints (/<base-path>/api/..., /<base-path>/static/...).
• Dynamic <base href> Injection: Injects <base href="/<base-path>/"> dynamically into index.html so the browser resolves relative asset requests and API calls cleanly.
• Automatic Trailing Slash Redirects: Requests to /<base-path> redirect to /<base-path>/, and root / redirects to the base path.
• Configurable in Settings: Can also be set permanently in ~/.px0/settings.json via server.basePath.

Headless CLI Options for Remote Hosts

When running px0 on remote machines, use these flags:

Security & Sandboxing Guarantees

When exposing px0 across networks:

• Exploration Sandboxing: File reading, search, and symbol endpoints are strictly sandboxed.
• Path Traversal Protection: Every request verifies that target file paths resolve strictly inside the designated workspace root.
• DNS Rebinding Prevention: The HTTP router verifies incoming Host headers to prevent cross-origin DNS rebinding attacks.
• Agent Editing Origin Verification (localPost): Agent dispatch endpoints (/api/agent/...) verify that the Origin matches the Host header and that the Host is an IP address or localhost. Access through public tunnel hostnames will refuse agent edits to prevent remote exploitation.
• Network Isolation: When exposing px0 with -host 0.0.0.0, ensure the port is accessible only over private networks (WireGuard, Tailscale, private VPCs) or pass -no-agent to prevent unwanted code execution.