Set the one origin that browsers, nodes, sandboxes and applications use to reach Core, and put a reverse proxy with HTTPS in front of it. This guide is for operators who expose Core beyond the machine it runs on.

Choose the public URL

OAC_PUBLIC_URL is the origin applications, nodes, sandboxes and self-hosted executors use. Web accepts only its host, so DNS rebinding cannot reach it. Core derives its other addresses from it, listed under OAC_PUBLIC_URL. It is an http or https origin without a path.

Situation	Public URL
Trial on this machine	http://localhost:8080, the default when --host is not 0.0.0.0 or the host has no private address
Local network	http://<private address>:8080, which the installer picks when --host is 0.0.0.0 and the default route has a private-network address
Beyond the local network	The HTTPS origin your reverse proxy serves, for example https://core.example
E2B backend	An HTTPS origin reachable from the internet and not loopback, because E2B's sandboxes call Core from E2B's cloud

Pass the origin as --public-url when you install, or change it later as described in Change the public URL. To install with a flag, see Installation options.

Listeners and access

The default installation publishes Web on --web-port (8080) at --host 0.0.0.0. Core and PostgreSQL publish no port. --host is an IPv4 or IPv6 address, without a port, scheme or zone. Use a concrete server IP in the browser, not a wildcard.

Service	Reachable from outside
Web	OAC_WEB_PORT on OAC_HOST. Behind a reverse proxy, install with --host 127.0.0.1
Core	Only through Web. /v1, /api/v1 and /docs pass through unchanged; signed-in console requests to /core/v1 carry the Core key. Web serves everything else itself; see Request boundary
PostgreSQL	No

Sandboxes are the isolation boundary; see Runtime and outer isolation.

Ports

The installer checks --web-port before it downloads images.

• --host is the address that port binds. 0.0.0.0 publishes Web on every IPv4 interface. 127.0.0.1 keeps Web on this machine.
• A busy port stops installation. It does not move to another port.

oac apply recreates Web when OAC_HOST or OAC_WEB_PORT changes.

Put Core behind HTTPS

Install with --host 127.0.0.1 and point your reverse proxy at Web, 127.0.0.1:8080 by default. The proxy must:

• Preserve Host. Web accepts only the host of OAC_PUBLIC_URL.
• Pass WebSocket upgrades on /api/v1. Nodes, sandbox Runtimes (E2B included) and self-hosted executors connect there.
• Not buffer or time out streams. /v1 streams Session events.
• Accept large uploads. Source files may reach 512 MiB plus multipart overhead; Core enforces the limits.

Caddy

core.example {
	reverse_proxy 127.0.0.1:8080
}

nginx

map $http_upgrade $connection_upgrade {
	default upgrade;
	''      close;
}

server {
	listen 443 ssl;
	server_name core.example;
	ssl_certificate     /etc/ssl/core.example/fullchain.pem;
	ssl_certificate_key /etc/ssl/core.example/privkey.pem;

	client_max_body_size 513m;

	location / {
		proxy_pass http://127.0.0.1:8080;
		proxy_http_version 1.1;
		proxy_set_header Host $http_host;
		proxy_set_header Upgrade $http_upgrade;
		proxy_set_header Connection $connection_upgrade;
		proxy_buffering off;
		proxy_read_timeout 1h;
		proxy_send_timeout 1h;
	}
}

Caddy obtains the certificate itself and passes Host and WebSockets by default. The nginx server block goes in the http context and needs a certificate you provide.

Then set OAC_PUBLIC_URL=https://core.example in ~/.oac/core/.env and run ~/.oac/core/oac apply.

Verify the routing

curl -s -o /dev/null -w '%{http_code}\n' -H 'OpenAI-Beta: agents=v1' https://core.example/v1/agents

401 means /v1 reached Core, which asks for a key. 404 means it reached Web: fix the proxy, or application calls and every node connection will fail. A node that logs HTTP 400 on the WebSocket upgrade sits behind a proxy that does not pass upgrades on /api/v1; see Troubleshooting.

TLS verification stays on everywhere. With a private certificate authority, node hosts, self-hosted machines and the Runtime image must trust it.

Try it locally with a quick tunnel

A Cloudflare quick tunnel gives a trial installation with external ingress a temporary public HTTPS address.

1. Start the tunnel: cloudflared tunnel --url http://127.0.0.1:8080. It prints an address such as https://random-words.trycloudflare.com.
2. Set that address as OAC_PUBLIC_URL in ~/.oac/core/.env and run ~/.oac/core/oac apply.

The address changes whenever cloudflared restarts; nodes bound to the old address must then be added again. Throughput is low, so a node's first Runtime download (about 500 MB) can be slow; see slow links.

Change the public URL

Point the reverse proxy at the new address first, then edit OAC_PUBLIC_URL in ~/.oac/core/.env and run oac apply. Afterwards:

• Nodes on the old address get no new sandboxes: remove them in Web and add them again.
• Existing sandboxes and executors keep working only while the old address still reaches this Core.
• Self-hosted executors must restart with the new remote_url, and their installer refuses an installation made for the old address: create new self-hosted Sessions and connect their hosts again.

The setting is listed in the Configuration reference.