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reCAPTCHA v2
reCAPTCHA v2
< 40s2$ / 1k
reCAPTCHA v3
reCAPTCHA v3
< 5s0,5$ / 1k
Kasada
Kasada
< 6s0,5$ / 1k
Akamai
Akamai
< 6s0,5$ / 1k
Cloudflare Turnstile
Cloudflare Turnstile
< 5s0,5$ / 1k
VK Captcha
VK Captcha
< 8s0,5$ / 1k
Castle
Castle
< 4s0,4$ / 1k
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Dedicated solver

Castle Solver API

Integrate Castle solving into your automation through one stable REST endpoint. Send the target details and receive a ready-to-use solution without maintaining custom bypass logic.

Start solvingRead the docs
Castle
Task typeCastle
Average speed< 4s
Price per 1,0000,4$ / 1k
How it works

Castle, without custom bypass code.

A predictable three-step flow that stays the same even when Castle changes its protection.

Send the Castle publishable key from the page and, if relevant, the event name for the action you're protecting (e.g. $login.succeeded). We return the X-Castle-Request-Token header value and a __cuid device id to send along with your request.

01

Submit the target

Send the page URL and the challenge-specific fields in a single API request.

02

We handle the challenge

CaptchaSolv routes the task to a specialized solver and tracks it until completion.

03

Use the solution

Receive the token, headers, cookies, or sensor payload required by your next request.

API integration

The same endpoint and response envelope across every supported solver.

POST /solve
Request
{
  "api_key": "YOUR_API_KEY",
  "type": "Castle",
  "site_url": "https://example.com/login",
  "data": {
    "pub_key": "pk_XXXXXXXXXXXXXXXXXXXXXXXX",
    "event": "$login.succeeded"}
}
Response200 OK
{
  "errorId": 0,
  "status": "ready",
  "solvtime": 1.94,
  "data": {
    "useragent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64)...",
    "language": "en-US,en;q=0.9",
    "solution": {
      "request_token": "eyJkYXRhIjoiZXlKe...",
      "cuid": "d290f1ee-6c54-4b01-90e6-d701748f0851"}
  }
}
Task data fields

Fields you can send inside the data object of a solve request for this captcha type.

pub_keyRequired

The Castle publishable key loaded by the page's Browser SDK, prefixed pk_.

eventOptional

The activity name being protected, e.g. $login.succeeded or $registration.succeeded. Improves signal accuracy when supplied.

Solution fields

Fields returned in data.solution once the task is solved.

solution.request_tokenRequired

Send as the X-Castle-Request-Token header on the protected request.

solution.cuidOptional

Device id to send as the __cuid cookie, for continuity across requests from the same simulated device.

data.useragentRequired

The user-agent used while generating the token - reuse it on the protected request.

Frequently asked questions

Common questions about integrating this solver correctly.

Yes - it works on any site using Castle's device fingerprinting and risk API, not just a fixed list of targets. Send the publishable key from the page you're hitting and we generate a valid request token for that specific integration.

Need help?

Stuck trying to bypass Castle?

Join our Discord and our team will help you get Castle solving working in your setup - free advice on handling it programmatically, even as the challenge changes over time.

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