Google’s own reCAPTCHA widgets carry an extra data-s value. Miss it and the token is rejected. Here is where it lives, what to call it in the SDK, and a working script.

Proxies apply to three of the four CAPTCHA families, and rotating on every request is what gets you blocked. Pin one IP per session, rotate on failure.

undetected-chromedriver gets you past the fingerprint checks, not past the widget. Here is how to read the sitekey, solve locally and inject the token in the same session.

Both codes come back from in.php before a task is ever created. The usual cause is sending sitekey where reCAPTCHA wants googlekey. Here is how to find and fix each one.

No SDK, no dependencies. Two curl calls against a local 2captcha-compatible API: submit the task, poll for the answer. Every method and parameter, with a working script.

Python’s AsyncCapSkip is a genuine async client, not an alias. Here is how to solve a batch of CAPTCHAs concurrently with asyncio.gather, capped and error-safe.

ERROR_CAPTCHA_UNSOLVABLE is a failed attempt, not a broken setup. Why re-polling the same ID never helps, the causes per CAPTCHA type, and a retry loop that works.

The best captcha solver in 2026, chosen on published rates and architecture rather than unverifiable accuracy claims, with the full dated price table for all ten services.

Put CAPTCHA handling in a downloader middleware, not in every spider. Detection, a non-blocking solve, the token resubmit, and the settings that matter.

ERROR_KEY_DOES_NOT_EXIST is a key mismatch, not a broken solver. The three causes, the fix in all four SDKs, and how it differs from ERROR_WRONG_USER_KEY.