How does Kasada bot-defense work?

Kasada serves an obfuscated JS challenge that must be evaluated client-side to produce an x-kpsdk-cd header. The gateway validates the header and lets traffic through. CaptchaSonic evaluates the challenge server-side and returns the header value.

Does CaptchaSonic handle x-kpsdk-ct?

Yes. Both x-kpsdk-cd (challenge) and x-kpsdk-ct (continuation) header flows are supported. Pass the page URL and user agent; receive both header values in 4–8 seconds.

Is the Kasada token tied to my proxy IP?

Yes. Solve from inside your egress IP — pass the proxy hostname/port/credentials to the createTask payload — so the returned headers fingerprint to the same address Kasada will see on subsequent requests.

KPSDK challenge solver

Kasada Bypass

Bypass Kasada bot-defense with CaptchaSonic. AI solver replays the x-kpsdk-cd challenge and returns the validated KPSDK token so headless clients pass Kasada's shield in one round trip.

Start Building Read Documentation

// CaptchaSonic — Kasada KPSDK solver
const sonic = new CaptchaSonic('YOUR_API_KEY');

const result = await sonic.solve({
  type: 'KasadaTask',
  websiteURL: 'https://target.example.com/protected',
  userAgent: 'Mozilla/5.0 (...)',
  proxy: { type: 'http', host: '...', port: 8080 }
});

// Attach Kasada headers to subsequent requests.
const headers = {
  'x-kpsdk-cd': result.cd,
  'x-kpsdk-ct': result.ct,
};

Why use Sonic for KPSDK challenge solver?

Built for speed, reliability, and easy integration.

x-kpsdk-cd + ct returned

Both the challenge and continuation headers are emitted in a single task response.

Obfuscated JS handled

Solver evaluates Kasada's obfuscated payload server-side — no headless browser on your side needed.

IP-bound fingerprint

Solve from inside your proxy so the token survives Kasada's ratelimit signals.

Built for Developers

Choose your language and start solving CAPTCHAs in seconds

Type-safe

Async/Await

Error Handling

View Full Documentation

index.js

import { CaptchaSonic } from 'captchasonic'

const client = new CaptchaSonic({
  apiKey: 'your_api_key'
})

// Solve reCAPTCHA
const result = await client.solve({
  type: 'recaptcha_v2',
  sitekey: 'site_key_here',
  pageurl: 'https://example.com'
})

console.log(result.solution)

99.9%

Success Rate

<0.5s

Avg Response

99.9%

Uptime

10k+

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