Third-Party Solvers: 2Captcha, CapSolver, Anti-Captcha

Which API pattern do major CAPTCHA solvers (2Captcha, CapSolver, Anti-Captcha) use?

• ASynchronous: submit request, response is the token immediately
• BSubmit task → receive task ID → poll for result every few seconds → receive token when ready
• CWebSocket streaming
• DEmail-based