Ports and preview links

Every port of a sandbox has a URL: https://<port>-<sandbox id>.sbx.compute.anonalabs.com. The SDK builds it for you with get_host. Who can open it depends on how you share it:

Way	Who gets in	Good for
Preview link	Anyone with the link, for one port, until it expires (1 minute to 24 hours)	Showing a dev server or app to a person
Public port	Anyone, on that port, until you make it private again	Webhook receivers, demos
Traffic token	Requests carrying the `e2b-traffic-access-token` header	Your own backend or proxy
Public sandbox (`allow_public_traffic`)	Anyone, on every port	Throwaway previews

Port 49983 (envd, which runs commands and files) is never shared: it always needs the sandbox’s own access token, which the SDK holds.

Preview links

anona-compute preview "$SANDBOX_ID" 3000              # prints a link, valid 1 hour
anona-compute preview "$SANDBOX_ID" 3000 --ttl 15m
anona-compute preview "$SANDBOX_ID" --revoke          # ends every link (and live-view token) of the sandbox

import os
import httpx

api = httpx.Client(base_url="https://api.compute.anonalabs.com", headers={"X-API-Key": os.environ["E2B_API_KEY"]})
sid = os.environ["SANDBOX_ID"]

link = api.post(f"/v1/sandboxes/{sid}/preview-links", json={"port": 3000, "ttlSeconds": 900}).json()
print(link["url"].split("?")[0], "expires", link["expiresAt"])

api.post(f"/v1/sandboxes/{sid}/preview-links:revoke-all").raise_for_status()

The link looks like https://3000-<id>.sbx.compute.anonalabs.com/?anona_sig=…&anona_exp=…. On the first visit the sandbox edge exchanges it for a cookie that is scoped to that one port’s host (Secure, HttpOnly, SameSite=Lax) and redirects to the same URL without the signature, so the app inside never sees it. Other ports and other sandboxes stay private. Revoking ends every link and every live-view token of the sandbox within a second. The dashboard’s sandbox page has Share preview, and agents get links from the MCP tool get_preview_url.

Public ports

public_port.sh

anona-compute preview "$SANDBOX_ID" 8080 --public     # anyone can open port 8080, no link needed
curl -sS "https://api.compute.anonalabs.com/v1/sandboxes/$SANDBOX_ID/access" -H "X-API-Key: $E2B_API_KEY" | jq -c .
anona-compute preview "$SANDBOX_ID" 8080 --private

Up to 64 public ports per sandbox. PUT /v1/sandboxes/{id}/ports/{port} with {"public": true} does the same over the API.

Traffic token

For your own services, keep the port private and send the sandbox’s traffic token:

private_port.py

import httpx
from anona import Sandbox

with Sandbox.create("python", network={"allow_public_traffic": False}) as sbx:
    sbx.commands.run("cd /tmp && python3 -m http.server 8000", background=True)
    sbx.commands.run("for i in $(seq 50); do curl -s localhost:8000 >/dev/null && break; sleep 0.1; done")
    url = "https://" + sbx.get_host(8000)
    print(httpx.get(url).status_code)  # refused without the token
    print(httpx.get(url, headers={"e2b-traffic-access-token": sbx.traffic_access_token}).status_code)

A request to a paused sandbox’s URL gets 409; resume it with Sandbox.connect first.

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Preview links

Public ports

Traffic token

​Preview links

​Public ports

​Traffic token

Preview links

Public ports

Traffic token