/unblock API

info

Currently, Browserless V2 is available in production via two domains: production-sfo.browserless.io and production-lon.browserless.io

The /unblock API is designed to bypass bot detection mechanisms, allowing you to get a bot-protected website's content, cookies, and even a screenshot of the bypassed result. It's available exclusively in cloud-hosted or Enterprise plans and only supports connections via the Chrome DevTools Protocol. Using the /unblock API is charged at 10 units per page.

This API is particularly useful for developers who need to automate web interactions on sites that employ sophisticated bot detection and blocking techniques.

You can check the full Open API schema here for all properties and documentation.

Basic Usage

JSON Payload

This is a JSON object containing the URL of the site you wish to unblock, along with the parameters you want in the response. Ideally you always want to set the ttl the browserWSEndpoint and cookies.

{
  "url": "https://example.com",
  "browserWSEndpoint": true,
  "cookies": true,
  "content": false,
  "screenshot": false,
  "ttl": 30000
}

cURL Request

curl --request POST \
  --url 'https://production-sfo.browserless.io/unblock?token=GOES-HERE' \
  --header 'content-type: application/json' \
  --data '{
  "url": "https://example.com",
  "browserWSEndpoint": true,
  "cookies": true,
  "content": false,
  "screenshot": false,
  "ttl": 30000
}'

Which will return a JSON response like this:

{
  "browserWSEndpoint": "wss://production-sfo.browserless.io/p/53616c7465645f5f0d2e4012516859fdda7cc1ae0b16c6c5ec739d5d9f19a3d3c9b49c8a814b0fd1beae934b2e8050a0/devtools/browser/102ea3e9-74d7-42c9-a856-1bf254649b9a",
  "content": null,
  "cookies": [
    {
      name: "session_id",
      value: "XYZ123",
      domain: "example.com",
      path: "/",
      secure: true,
      httpOnly: true,
    },
  ],
  "screenshot": null,
  "ttl": 30000
}

After receiving the response with the browserWSEndpoint and cookies, you can use Puppeteer, Playwright or another CDP library to connect to the browser instance and inject the cookies to continue your scraping process:

Puppeteer Connection

import puppeteer from "puppeteer";
import unblock from "./utils";

// Example response from the API
const { browserWSEndpoint, cookies } = unblock("https://example.com");

const browser = await puppeteer.connect({ browserWSEndpoint });
const page = await browser.newPage();

// Inject cookies into the page
await page.setCookie(...response.cookies);
await page.goto("https://www.targetsite.com");
await page.screenshot({ path: "screenshot.png" });

await browser.close();

Waiting for Things

Browserless offers 4 different ways to wait for preconditions to be met on the page before returning the response. These are events, functions, selectors and timeouts.

waitForEvent

Waits for an event to happen on the page before continuing:

Example

JSON payload

// Will fail since the event never fires on this page,
// but used for demonstration purposes
{
  "url": "https://example.com/",
  "waitForEvent": {
    "event": "fullscreenchange",
    "timeout": 5000
  }
}

cURL request

curl -X POST \
  https://production-sfo.browserless.io/unblock?token=MY_API_TOKEN \
  -H 'Cache-Control: no-cache' \
  -H 'Content-Type: application/json' \
  -d '{
  "url": "https://example.com/",
  "waitForEvent": {
    "event": "fullscreenchange",
    "timeout": 5000
  }
}'

waitForFunction

Waits for the provided function to return before continuing. The function can be any valid JavaScript function including async functions.

Example

JS function

async () => {
  const res = await fetch("https://jsonplaceholder.typicode.com/todos/1");
  const json = await res.json();

  document.querySelector("h1").innerText = json.title;
};

JSON payload

{
  "url": "https://example.com/",
  "waitForFunction": {
    "fn": "async()=>{let t=await fetch('https://jsonplaceholder.typicode.com/todos/1'),e=await t.json();document.querySelector('h1').innerText=e.title}",
    "timeout": 5000
  }
}

cURL request

curl -X POST \
  https://production-sfo.browserless.io/unblock?token=MY_API_TOKEN \
  -H 'Cache-Control: no-cache' \
  -H 'Content-Type: application/json' \
  -d '{
  "url": "https://example.com/",
  "waitForFunction": {
    "fn": "async()=>{let t=await fetch('https://jsonplaceholder.typicode.com/todos/1'),e=await t.json();document.querySelector('h1').innerText=e.title}",
    "timeout": 5000
  }
}'

waitForSelector

Waits for a selector to appear on the page. If at the moment of calling this API, the selector already exists, the method will return immediately. If the selector doesn't appear after the timeout milliseconds of waiting the API will return a non-200 response code with an error message as the body of the response.

The object can have any of these values:

• selector: String, required — A valid CSS selector.
• hidden Boolean, optional — Wait for the selected element to not be found in the DOM or to be hidden, i.e. have display: none or visibility: hidden CSS properties.
• timeout: Number, optional — Maximum number of milliseconds to wait for the selector before failing.
• visible: Boolean, optional — Wait for the selected element to be present in DOM and to be visible, i.e. to not have display: none or visibility: hidden CSS properties.

Example

JSON payload

{
  "url": "https://example.com/",
  "waitForSelector": {
    "selector": "h1",
    "timeout": 5000
  }
}

cURL request

curl -X POST \
  https://production-sfo.browserless.io/unblock?token=MY_API_TOKEN \
  -H 'Cache-Control: no-cache' \
  -H 'Content-Type: application/json' \
  -d '{
  "url": "https://example.com/",
  "waitForSelector": {
    "selector": "h1",
    "timeout": 5000
  }
}'