Cloudflare Interstitial Solver API

Solve Cloudflare interstitial challenge pages with the Solverify Cloudflare Interstitial Solver API. The browser-based task returns Cloudflare session cookies, including cf_clearance when available, together with the solver user-agent and optional post-challenge HTML.

Use this task type when an authorized integration must continue a request with the same proxy, cookies, and browser identity used during the solved Cloudflare session.

The integration follows the standard Solverify task workflow:

Create an interstitial task with the target URL and proxy.
Store the returned taskId.
Poll POST /getTaskResult until processing completes.
Read cookies from solution.cookies.
Replay the cookies with the same proxy and solution.useragent.

Request Parameters

Field	Type	Required	Description
`clientKey`	string	Yes	Your private Solverify API key.
`task.type`	string	Yes	Must be `interstitial`.
`task.websiteURL`	string	Yes	Full URL of the Cloudflare-protected target page. Maximum 2,048 characters.
`task.useragent`	string	No	Chrome-family user-agent to use for the browser session. Desktop Chrome/Chromium and compatible Android Chrome user-agents are supported.
`task.source`	boolean	No	When `true`, requests post-challenge page HTML in `solution.html`. Default: `false`.
`task.method`	string	No	Navigation method. Accepted values: `GET` and `POST`. Default: `GET`.
`task.proxyType`	string	Yes	Proxy type. Only `http` is accepted.
`task.proxyAddress`	string	Yes	Proxy IP address or hostname. Maximum 256 characters.
`task.proxyPort`	string	Yes	Proxy port as a numeric string containing 1 to 5 digits.
`task.proxyLogin`	string	No	Username for an authenticated proxy.
`task.proxyPassword`	string	No	Password for an authenticated proxy.

Replay the returned Cloudflare cookies with the same proxy and the exact user-agent in solution.useragent. Changing either can invalidate the solved session.

If you provide useragent, use desktop Chrome/Chromium or Android Chrome. Android user-agents are accepted only when the solver can generate a compatible device fingerprint. Firefox, Edge, Opera, iOS, and non-Chrome Android user-agents are rejected.

Create Interstitial Task Request

{
  "clientKey": "YOUR_API_KEY",
  "task": {
    "type": "interstitial",
    "websiteURL": "https://example.com",
    "useragent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36",
    "source": true,
    "method": "GET",
    "proxyType": "http",
    "proxyAddress": "1.1.1.1",
    "proxyPort": "8080",
    "proxyLogin": "username",
    "proxyPassword": "password"
  }
}

Omit proxyLogin and proxyPassword when the proxy does not require authentication. Omit useragent to let the solver use its browser user-agent, which is returned with the completed solution.

Cloudflare Interstitial Code Examples

These examples create an interstitial task and print the returned task ID.

curl --request POST \
  --url https://solver.solverify.net/createTask \
  --header "Content-Type: application/json" \
  --data '{
    "clientKey": "YOUR_API_KEY",
    "task": {
      "type": "interstitial",
      "websiteURL": "https://example.com",
      "source": true,
      "method": "GET",
      "proxyType": "http",
      "proxyAddress": "1.1.1.1",
      "proxyPort": "8080"
    }
  }'

Create Task Response

{
  "errorId": 0,
  "taskId": "UUID"
}

Completed Interstitial Result

{
  "errorId": 0,
  "status": "completed",
  "solution": {
    "value": "dce6748725944f29b43b64a5eaad3a",
    "cookies": {
      "cf_clearance": ".AdOHyy60coo8q0wL6TAJFu2V1"
    },
    "useragent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36",
    "html": "<html>...</html>"
  },
  "errorCode": null,
  "errorDescription": null
}

Solution Fields

Field	Description
`value`	Task-specific captured value or clearance value returned by the solved session.
`cookies`	Cookies from the solved browser session, including `cf_clearance` when available.
`useragent`	User-agent used by the solver. Replay cookies with this exact value.
`html`	Post-challenge page HTML. Present only when `source` is `true` and HTML was captured.

Cloudflare Interstitial Timeout

Cloudflare Interstitial tasks can run for up to approximately 120 seconds before timing out internally. Set an overall polling deadline in your application and stop when the API returns an error.

Cloudflare Interstitial API Errors

Error code	Description
`ERROR_INVALID_REQUEST`	The top-level request body is missing or contains invalid JSON.
`ERROR_INVALID_TASK`	Required interstitial fields or proxy settings are missing or invalid.
`ERROR_INSUFFICIENT_BALANCE`	The account balance is too low to create the task.
`ERROR_NO_CAPACITY`	Interstitial solver capacity is temporarily unavailable.
`ERROR_TASK_FAILED`	The Cloudflare interstitial challenge could not be completed.
`ERROR_TIMEOUT`	Solving exceeded the allowed processing time.

For recovery guidance and all supported errors, see Solverify API Error Codes.

Next Steps

After creating a Cloudflare Interstitial task, poll the Get Task Result API every 2 to 3 seconds with the returned taskId. Stop polling after completion or failure.

Frequently Asked Questions

What does the Cloudflare Interstitial Solver API return?

It returns cookies from the solved browser session, the solver user-agent, and optional post-challenge HTML. A successful session commonly includes cf_clearance in solution.cookies.

Is a proxy required?

Yes. Provide proxyType, proxyAddress, and proxyPort. Add proxyLogin and proxyPassword when authentication is required.

Why must I reuse the same proxy and user-agent?

Cloudflare clearance cookies are associated with the solved browser session. Reusing the proxy and solution.useragent preserves the session context for follow-up requests.

Can I choose the browser user-agent?

Yes. Provide a supported desktop Chrome/Chromium or Android Chrome user-agent in task.useragent. Android Chrome requires a compatible device fingerprint. You can also omit the field and replay the user-agent returned in solution.useragent.

How do I return the HTML after the challenge?

Set task.source to true. The html field is included when the challenge completes and the post-challenge page source is captured.

Use GET or POST in task.method. If the field is omitted, the solver uses GET.