Handling CAPTCHA Events

Find out how Unblocking Browser captures and handles CAPTCHA events.

Oxylabs provides two ways to monitor the CAPTCHA solving process. While console logging is currently available, it is scheduled for deprecation. We strongly recommend using the Event-Based Method for all new projects to ensure long-term compatibility and more reliable automation synchronization.

Event-Based Method (Recommended)

This method allows your script to listen for custom messages sent directly from the extension. It is more robust than log-watching as it avoids issues with console buffer limits or log filtering.

How it works

The extension sends a message to the browser's window object. You can capture these by adding a "message" event listener.

oxylabs-captcha-solve-start	The CAPTCHA is detected and solving has begun.
oxylabs-captcha-solve-end	The CAPTCHA was successfully solved.
oxylabs-captcha-solve-error	The auto-solver failed to bypass the CAPTCHA.

You can subscribe to these events to pause your automation and resume only after the CAPTCHA has been successfully handled. Normally, CAPTCHA solving takes up to 30 seconds, depending on the type and complexity of the CAPTCHA, but in some cases could take longer, so allow time for CAPTCHA solving to end.

Code samples

Python (Playwright)

import sys
from playwright.sync_api import sync_playwright

# Configuration
EXTENSION_NAME = 'oxylabs-runtime'
CAPTCHA_SOLVE_END = 'oxylabs-captcha-solve-end'
CAPTCHA_SOLVE_ERROR = 'oxylabs-captcha-solve-error'
UB_BROWSER_URL = 'wss://<username>:<password>@ubc.oxylabs.io'
CAPTCHA_CHECK_TIMEOUT_SEC = 60
TARGET_URL = 'https://www.indeed.com/cmp/Bank-of-the-West/reviews?lang=any&fcountry=ALL&sort=date'

def run():
    with sync_playwright() as p:
        print('Opening browser page...')
        # Connect to the remote browser using CDP
        browser = p.chromium.connect_over_cdp(UB_BROWSER_URL)
        
        # Get the default context and create a new page
        ctx = browser.contexts[0]
        page = ctx.new_page()

        # This must be done BEFORE navigation.
        ctx.add_init_script(f"""
            window.addEventListener("message", (event) => {{
                if (event.data && event.data.source === "{EXTENSION_NAME}") {{
                    window.__extensionStatus = event.data.type;
                }}
            }});
        """)

        print('Opening target website...')
        page.goto(TARGET_URL, wait_until='domcontentloaded')

        try:
            # Wait for the extension status to change
            page.wait_for_function(
                """
                ([solveEnd, solveError]) => {
                    const status = window.__extensionStatus;
                    if (status === solveError) {
                        throw new Error("CAPTCHA solving failed");
                    }
                    return status === solveEnd;
                }
                """,
                arg=[CAPTCHA_SOLVE_END, CAPTCHA_SOLVE_ERROR],
                timeout=CAPTCHA_CHECK_TIMEOUT_SEC * 1000
            )
            print('CAPTCHA solved successfully, continue scraping...')
            
        except Exception as err:
            print(f'Error during CAPTCHA solve: {err}')
            browser.close()
            sys.exit(1)

        page.wait_for_selector('h1[data-testid="PageHeader-title-reviews"]')
        page.screenshot(path='page_screenshot.jpg')

        page.close()
        browser.close()
        print('Done.')

if __name__ == "__main__":
    run()

JavaScript (Playwright)

JavaScript (Puppeteer)

Console Log Method (Legacy)

Note: This method is available only from Chrome browser and will be deprecated in a future release. Existing users should plan to migrate to the Event-Based method.

Oxylabs logs a message to the console when a CAPTCHA is detected and is in the process of being solved. Following messages can be printed into console log:

oxylabs-captcha-solve-start	Fired when our system has detected the CAPTCHA and started solving it.
oxylabs-captcha-solve-end	Fired when the auto-solver has successfully solved the CAPTCHA.
oxylabs-captcha-solve-error	Fired when the auto-solver has failed to solve the CAPTCHA.

You can subscribe to these events to pause your automation and resume only after the CAPTCHA has been successfully handled. Normally CAPTCHA solving takes up to 30 seconds depending on the type and complexity of the CAPTCHA, but in some cases could take longer so allow time for CAPTCHA solving to end.

Check out the below example of how these events can be handled.

Python (Playwright)

import asyncio
import time
from typing import Any

from playwright.async_api import async_playwright


# Fill in the username and password
UB_USERNAME: str = ""
UB_PASSWORD: str = ""
UB_BROWSER_URL: str = f"wss://{UB_USERNAME}:{UB_PASSWORD}@ubc-us.oxylabs.io"


class UBScraper:
    def __init__(self) -> None:
        self.OXYLABS_CAPTCHA_START_MESSAGE: str = "oxylabs-captcha-solve-start"
        self.OXYLABS_CAPTCHA_DONE_MESSAGE: str = "oxylabs-captcha-solve-end"

        self.CAPTCHA_STARTED: bool = True
        self.CAPTCHA_SOLVED: bool = False

    async def handle_console(self, msg: Any) -> None:
        msg_args = msg.args

        for arg in msg_args:
            log_message = str(arg)
            print(log_message)

            if log_message.strip() == self.OXYLABS_CAPTCHA_START_MESSAGE:
                print("Captcha started to solve!")
                self.CAPTCHA_STARTED = True
            if log_message.strip() == self.OXYLABS_CAPTCHA_DONE_MESSAGE:
                print("Captcha finished solving!")
                self.CAPTCHA_SOLVED = True

    async def wait_for_captcha_completion(self, timeout_seconds: int = 20) -> bool:
        start_time = time.time()
        check_interval = 1

        print(f"Waiting for captcha to complete (timeout: {timeout_seconds}s)")

        while not self.CAPTCHA_SOLVED:
            elapsed = time.time() - start_time

            if elapsed > timeout_seconds:
                print(f"Timeout after {elapsed:.1f}s waiting for captcha")
                return False

            if int(elapsed) % 5 == 0:
                print(f"Still waiting for captcha... ({int(elapsed)}s)")

            await asyncio.sleep(check_interval)

        completion_time = time.time() - start_time
        print(f"Captcha completed after {completion_time:.1f}s")
        return True

    async def scrape(self, url: str) -> None:
        async with async_playwright() as playwright:
            start = time.time()

            browser = await playwright.chromium.connect_over_cdp(
                UB_BROWSER_URL,
            )

            print(f"Connecting to browser took {time.time() - start:.2f} seconds")
            context = browser.contexts[0]
            page = await context.new_page()

            page.on("console", self.handle_console)

            await page.goto(url)

            captcha_completed = await self.wait_for_captcha_completion(
                timeout_seconds=30
            )

            if not captcha_completed:
                raise Exception("Failed to solve")

            await page.screenshot(path="cf_captcha_check_.png")
            print("done")

            input("Enter to close")


if __name__ == "__main__":
    import asyncio

    # replace with URL of your choice
    URL = "https://www.indeed.com/cmp/Bank-of-the-West/reviews?lang=any&fcountry=ALL&sort=date"

    asyncio.run(UBScraper().scrape(URL))

JavaScript (Playwright)

JavaScript (Puppeteer)