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Documentation Index

Fetch the complete documentation index at: https://docs.reader.dev/llms.txt

Use this file to discover all available pages before exploring further.

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CDP WebSocket Proxy

After creating a session, connect to the CDP WebSocket endpoint to control the browser.

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Endpoint

WSS /v1/sessions/{id}/cdp?token={token}
The wsEndpoint returned by POST /v1/sessions includes the full URL with token. Pass it directly to Playwright or Puppeteer.

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Authentication

The WebSocket proxy authenticates via the token query parameter (not the API key). The token is returned in the session creation response and is tied to that specific session.

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Playwright

const session = await reader.sessions.create();
const browser = await chromium.connectOverCDP(session.wsEndpoint);
const context = await browser.newContext();
const page = await context.newPage();

await page.goto("https://example.com");
console.log(await page.title());

await page.screenshot({ path: "screenshot.png" });
await page.pdf({ path: "page.pdf" });

const cookies = await context.cookies();

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Puppeteer

const session = await reader.sessions.create();
const browser = await connect({
  browserWSEndpoint: session.wsEndpoint,
  defaultViewport: null,
});

const page = await browser.newPage();
await page.goto("https://example.com");

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Raw CDP

const ws = new WebSocket(session.wsEndpoint);

// Create a page
const target = await sendCDP(ws, "Target.createTarget", { url: "about:blank" });
const attached = await sendCDP(ws, "Target.attachToTarget", {
  targetId: target.targetId,
  flatten: true,
});

// Navigate
await sendPageCDP(ws, attached.sessionId, "Page.navigate", {
  url: "https://example.com",
});

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Blocked CDP Commands

The proxy filters dangerous CDP commands for security. These methods are blocked and return a JSON-RPC error:
MethodReason
Browser.closeWould kill the browser process
Target.createBrowserContextResource abuse, bypasses isolation
Target.disposeBrowserContextCould destroy the session context
SystemInfo.getProcessInfoLeaks server process information
All other CDP methods (Page, Runtime, Network, DOM, etc.) pass through normally.

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Error Response for Blocked Commands

{
  "id": 42,
  "error": {
    "code": -32601,
    "message": "Method not allowed: Browser.close"
  }
}

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Connection Lifecycle

  • Connect: Playwright/Puppeteer opens a WebSocket to the proxy URL
  • Relay: The proxy authenticates the token and relays CDP frames to the browser
  • Disconnect: When either side closes, the other is also closed
  • Timeout: Sessions auto-close after the configured timeout

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Stealth

The browser has anti-bot stealth active regardless of which client connects:
  • navigator.webdriver = false
  • Navigator/WebGL/WebRTC spoofing
  • Chrome plugin array simulation
These are injected at the browser level and apply to all pages, including new pages created by Playwright/Puppeteer.