Browser Use

The browser image ships a resident, headless Chromium with its DevTools/CDP endpoint open. You drive it from your client with Playwright over CDP, all the automation logic lives in your code, and the browser runs isolated in the sandbox.

Connect Playwright over CDP

Attach to the sandbox's Chromium through the proxy and drive it as if it were local. Chromium's CDP endpoint listens on port 9223 inside the sandbox, exposed at a stable /cdp path.

index.ts

import * as hiver from "@hiver.sh/client";
import { chromium } from "playwright-core";

const sandbox = await hiver.getOrCreateSandbox("browser", { image: "browser" });

// Build the CDP WebSocket URL: proxy URL for port 9223, http -> ws, + /cdp
const wsEndpoint = sandbox.proxyUrl(9223).replace(/^http/, "ws") + "cdp";

const browser = await chromium.connectOverCDP(wsEndpoint);
const context = browser.contexts()[0];
const page = context.pages()[0] ?? (await context.newPage());

await page.goto("https://news.ycombinator.com", { waitUntil: "domcontentloaded" });
const titles = await page.$$eval(".titleline > a", (els) => els.map((e) => e.textContent));
console.log(titles);

await browser.close(); // disconnects the client; the sandbox browser stays warm

import * as hiver from "@hiver.sh/client";
import { chromium } from "playwright-core";

const sandbox = await hiver.getOrCreateSandbox("browser", { image: "browser" });

// Build the CDP WebSocket URL: proxy URL for port 9223, http -> ws, + /cdp
const wsEndpoint = sandbox.proxyUrl(9223).replace(/^http/, "ws") + "cdp";

const browser = await chromium.connectOverCDP(wsEndpoint);
const context = browser.contexts()[0];
const page = context.pages()[0] ?? (await context.newPage());

await page.goto("https://news.ycombinator.com", { waitUntil: "domcontentloaded" });
const titles = await page.$$eval(".titleline > a", (els) => els.map((e) => e.textContent));
console.log(titles);

await browser.close(); // disconnects the client; the sandbox browser stays warm

browser.close() only disconnects your CDP client, it does not kill the resident browser, so the sandbox stays warm for the next attach. Your local Playwright version is independent of the Chromium baked into the image, because CDP is a wire protocol.

Why this is fast

Under microVM isolation the warm browser is captured in the sandbox snapshot, so a resumed sandbox comes back with Chromium already listening, no cold browser launch on the critical path. Reuse the resident context and page (rather than creating new ones) to keep that speed.

Driving a browser from inside

Alternatively, run a browser-automation script inside the sandbox with execStream, launch Chromium once in a REPL session and reuse it across many page loads, paying the startup cost a single time. This keeps all traffic within the sandbox and is a good fit for agent-authored scripts.

Go clients can drive the same CDP endpoint with a library like chromedp or rod, point it at the /cdp WebSocket URL above.

Let an agent drive the browser

The examples above put you in control of the browser. If you'd rather let an agent browse, load a JS-heavy or login-gated page, click, type, fill a form, read the page, the agent images ship a ready-made browser skill. It's a Claude Code skill that drives the sandbox's headless Chrome over CDP, reading the accessibility tree to understand pages and interacting with stable selectors.

You don't call the skill directly, Claude discovers it and uses it on its own when a task needs a browser. Just run Claude Code with a browsing prompt:

index.ts

import { getOrCreateSandbox } from "@hiver.sh/client";

const sandbox = await getOrCreateSandbox("browser-agent", {
  image: "browser",
  env: { ANTHROPIC_API_KEY: process.env.ANTHROPIC_API_KEY! },
});

const result = await sandbox.exec(
  ["claude", "-p", "Open news.ycombinator.com and list the top 5 story titles"],
  { cwd: "/workspace" },
);
console.log(result.stdout);

import { getOrCreateSandbox } from "@hiver.sh/client";

const sandbox = await getOrCreateSandbox("browser-agent", {
  image: "browser",
  env: { ANTHROPIC_API_KEY: process.env.ANTHROPIC_API_KEY! },
});

const result = await sandbox.exec(
  ["claude", "-p", "Open news.ycombinator.com and list the top 5 story titles"],
  { cwd: "/workspace" },
);
console.log(result.stdout);

Behind the scenes the skill starts a small CDP bridge, attaches to the page, and drives Chrome, the agent handles all of that. Watch it work live in the Inspector's Terminal, and stream the output for long sessions. To ship your own skills (or tweak this one), mount a skills directory with origin, see skill iteration.

Next: Python Sandbox