aiohttp + CaptchaAI: Async CAPTCHA Solving

aiohttp enables non-blocking HTTP requests in Python. Combine it with CaptchaAI to solve multiple CAPTCHAs concurrently without blocking your event loop.

Requirements

Requirement	Details
Python	3.8+
aiohttp	3.8+
CaptchaAI API key	Get one here

pip install aiohttp

Async CaptchaAI Client

import aiohttp
import asyncio


class AsyncCaptchaAI:
    def __init__(self, api_key):
        self.api_key = api_key
        self.base_url = "https://ocr.captchaai.com"

    async def submit(self, session, params):
        """Submit a CAPTCHA task and return the task ID."""
        params["key"] = self.api_key
        async with session.get(
            f"{self.base_url}/in.php", params=params
        ) as resp:
            text = await resp.text()

        if not text.startswith("OK|"):
            raise Exception(f"Submit failed: {text}")

        return text.split("|")[1]

    async def poll(self, session, task_id, timeout=300):
        """Poll for the result with a timeout."""
        params = {
            "key": self.api_key,
            "action": "get",
            "id": task_id,
        }
        deadline = asyncio.get_event_loop().time() + timeout

        while asyncio.get_event_loop().time() < deadline:
            await asyncio.sleep(5)

            async with session.get(
                f"{self.base_url}/res.php", params=params
            ) as resp:
                text = await resp.text()

            if text == "CAPCHA_NOT_READY":
                continue
            if text.startswith("OK|"):
                return text.split("|", 1)[1]
            raise Exception(f"Solve failed: {text}")

        raise TimeoutError(f"Task {task_id} timed out after {timeout}s")

    async def solve(self, session, params, timeout=300):
        """Submit and poll in one call."""
        task_id = await self.submit(session, params)
        return await self.poll(session, task_id, timeout)

    async def get_balance(self, session):
        """Check account balance."""
        params = {"key": self.api_key, "action": "getbalance"}
        async with session.get(
            f"{self.base_url}/res.php", params=params
        ) as resp:
            return float(await resp.text())

Solve a Single CAPTCHA

import asyncio
import os

async def main():
    solver = AsyncCaptchaAI(os.environ["CAPTCHAAI_API_KEY"])

    async with aiohttp.ClientSession() as session:
        # Check balance
        balance = await solver.get_balance(session)
        print(f"Balance: ${balance:.2f}")

        # Solve reCAPTCHA v2
        token = await solver.solve(session, {
            "method": "userrecaptcha",
            "googlekey": "6Le-wvkS...",
            "pageurl": "https://example.com",
        })
        print(f"Token: {token[:50]}...")

asyncio.run(main())

Solve Multiple CAPTCHAs Concurrently

async def solve_batch(urls, site_key):
    solver = AsyncCaptchaAI(os.environ["CAPTCHAAI_API_KEY"])

    async with aiohttp.ClientSession() as session:
        tasks = [
            solver.solve(session, {
                "method": "userrecaptcha",
                "googlekey": site_key,
                "pageurl": url,
            })
            for url in urls
        ]

        results = await asyncio.gather(*tasks, return_exceptions=True)

        for url, result in zip(urls, results):
            if isinstance(result, Exception):
                print(f"FAILED {url}: {result}")
            else:
                print(f"SOLVED {url}: {len(result)} chars")

        return results


urls = [
    "https://example.com/page1",
    "https://example.com/page2",
    "https://example.com/page3",
    "https://example.com/page4",
    "https://example.com/page5",
]
asyncio.run(solve_batch(urls, "6Le-wvkS..."))

Scraping with CAPTCHA Handling

async def scrape_with_captcha(url, site_key):
    solver = AsyncCaptchaAI(os.environ["CAPTCHAAI_API_KEY"])

    async with aiohttp.ClientSession() as session:
        # Fetch the page
        async with session.get(url) as resp:
            html = await resp.text()

        # Check if page has a CAPTCHA
        if "g-recaptcha" not in html:
            return html  # No CAPTCHA, return content

        # Solve the CAPTCHA
        token = await solver.solve(session, {
            "method": "userrecaptcha",
            "googlekey": site_key,
            "pageurl": url,
        })

        # Submit with solved token
        async with session.post(url, data={
            "g-recaptcha-response": token,
        }) as resp:
            return await resp.text()

Semaphore for Rate Control

Limit concurrent solves to avoid overwhelming the API:

async def solve_with_limit(urls, site_key, max_concurrent=10):
    solver = AsyncCaptchaAI(os.environ["CAPTCHAAI_API_KEY"])
    semaphore = asyncio.Semaphore(max_concurrent)

    async def solve_one(session, url):
        async with semaphore:
            return await solver.solve(session, {
                "method": "userrecaptcha",
                "googlekey": site_key,
                "pageurl": url,
            })

    async with aiohttp.ClientSession() as session:
        tasks = [solve_one(session, url) for url in urls]
        results = await asyncio.gather(*tasks, return_exceptions=True)

    solved = sum(1 for r in results if not isinstance(r, Exception))
    print(f"Solved {solved}/{len(urls)} CAPTCHAs")
    return results

Turnstile Example

async def solve_turnstile(url, sitekey):
    solver = AsyncCaptchaAI(os.environ["CAPTCHAAI_API_KEY"])

    async with aiohttp.ClientSession() as session:
        token = await solver.solve(session, {
            "method": "turnstile",
            "sitekey": sitekey,
            "pageurl": url,
        })
        return token

Troubleshooting

Error	Cause	Fix
`ClientConnectorError`	Network issue	Check connectivity
`Submit failed: ERROR_ZERO_BALANCE`	No funds	Top up account
`TimeoutError`	Slow solve	Increase timeout parameter
`RuntimeError: Event loop is closed`	Using `asyncio.run` in Jupyter	Use `nest_asyncio`

FAQ

Why aiohttp instead of httpx?

aiohttp is the most mature async HTTP library in Python with the best performance for high-concurrency workloads. httpx also works — see our httpx integration guide.