Create a task

POST https://api.noptcha.com/createTask

Compatibility API (anti-captcha compatible). Guide. Operation ID compatCreateTask.

Creates a task and returns its integer taskId; poll it with /getTaskResult.

When the solver answers synchronously (image types on our own models), the response already has status: "ready", solution and cost; polling it afterwards returns the same result. When such a synchronous attempt fails, the response is the task's error (for example ERROR_CAPTCHA_UNSOLVABLE) and no task ID is returned; nothing is charged.

softId / appId (digits) are recorded with the task for the developer programme.

Request

Authentication: the key in the clientKey body field (Keys).

Body (application/json, required):

Field	Type	Description
clientKey required	string	Your key (nop_live_… or nop_test_…).
appId optional	integer | string	Same as softId.
callbackUrl optional	string	Where to POST the final result (the getTaskResult response plus taskId, see the compatCallback webhook). Same rules as v1 callback_url; an invalid URL is ERROR_INCORRECT_SESSION_DATA. Empty: no callback. max length 2,048
softId optional	integer | string	Developer programme ID (digits); recorded with the task.
task required	object	The task in anti-captcha's format: type (see CompatTaskType) plus that type's fields (websiteURL, websiteKey, body, …; the field map per name is in CompatTaskType). Unknown fields are ignored. Parameters are validated against the canonical type's schema (see CreateTaskRequest). Proxy names (…Task, without Proxyless) need a proxy: proxyType (http, https, socks4, socks5), proxyAddress, proxyPort, optional proxyLogin and proxyPassword; or proxy as a URL string http://user:pass@host:port. Proxyless names ignore proxy fields.
task.proxyAddress optional	string
task.proxyLogin optional	string
task.proxyPassword optional	string
task.proxyPort optional	integer | string
task.proxyType optional	enum	one of "http", "https", "socks4", "socks5"
task.type required	string	Task type name in the compatibility API (case-insensitive). Each name maps to a canonical type and variant (see CreateTaskRequest for the parameters). Names ending in Proxyless ignore proxy fields; the others require a proxy. Unknown names: ERROR_TASK_NOT_SUPPORTED. x-noptcha-aliases lists, per name, fields (compatibility field → canonical parameter; null: accepted but not passed on; to_array: a single value is wrapped in an array) and solution (canonical solution field → compatibility field; index_bools: selected indexes become one boolean per image or tile). Name Canonical type Variant Notes FunCaptchaClassification image.funcaptcha proxyless FunCaptchaTask funcaptcha proxy FunCaptchaTaskProxyless funcaptcha proxyless HCaptchaClassification image.grid.hcaptcha proxyless HCaptchaTask hcaptcha proxy HCaptchaTaskProxyless hcaptcha proxyless ImageToTextTask image.text proxyless NoCaptchaTask recaptcha.v2 proxy NoCaptchaTaskProxyless recaptcha.v2 proxyless ReCaptchaV2Classification image.grid.recaptcha proxyless RecaptchaV2EnterpriseTask recaptcha.v2.enterprise proxy RecaptchaV2EnterpriseTaskProxyless recaptcha.v2.enterprise proxyless RecaptchaV2Task recaptcha.v2 proxy RecaptchaV2TaskProxyless recaptcha.v2 proxyless RecaptchaV3EnterpriseTask recaptcha.v3.enterprise proxyless RecaptchaV3TaskProxyless recaptcha.v3 proxyless isEnterprise: true → recaptcha.v3.enterprise TurnstileTask turnstile proxy TurnstileTaskProxyless turnstile proxyless

Example

{
  "clientKey": "nop_live_XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX",
  "task": {
    "type": "RecaptchaV2TaskProxyless",
    "websiteKey": "6Le-wvkSAAAAAPBMRTvw0Q4Muexq9bi0DJwx_mJ-",
    "websiteURL": "https://example.com/login"
  }
}

Responses

200

Created (errorId 0) or rejected (errorId 1).

Headers: Noptcha-Request-Id.

Content: application/json

One of:

• CompatCreateTaskResult
• CompatError — A request or task error. errorCode values (anti-captcha's codes; new ones may be added):

403

forbidden (problem details): the request reached the API without passing through our edge network. Infrastructure, not part of the compatibility protocol.

Headers: Noptcha-Request-Id.

Content: application/problem+json

Field	Type	Description
code required	string	Machine-readable error code (see the table).
detail optional	string	Human-readable explanation of this occurrence.
request_id required	string	Same as the Noptcha-Request-Id header.
status required	integer	The HTTP status code.
title required	string
type required	string	format: uri

500

internal: an error on our side.

Headers: Noptcha-Request-Id, RateLimit (optional), RateLimit-Policy (optional).

Content: application/problem+json

Field	Type	Description
code required	string	Machine-readable error code (see the table).
detail optional	string	Human-readable explanation of this occurrence.
request_id required	string	Same as the Noptcha-Request-Id header.
status required	integer	The HTTP status code.
title required	string
type required	string	format: uri

About the compatibility API:

The anti-captcha compatible JSON protocol.

• Requests are POST with a JSON body. Content-Type is not required; the body is always parsed as JSON.
• The key goes in clientKey. The key is checked before anything else, so an invalid key is reported even when other fields are wrong.
• Responses are always HTTP 200. errorId is 0 on success and 1 on error; then errorCode and errorDescription say what went wrong (see CompatError for every code).
• Two responses come from the infrastructure, not from the protocol: 403 (problem details, code forbidden) when a request reaches the API without passing through our edge network, and 500 (code internal) on an unexpected server error. Treat both as transient errors.
• An unknown path, or a known path with another method (for example GET /createTask), is 404 (problem details, code not_found).
• Task type names are the common anti-captcha compatible names (case-insensitive); each maps to a canonical type and variant, see CompatTaskType.
• callbackUrl (optional) receives the final result as a POST (see Webhooks and the compatCallback webhook). An invalid URL is ERROR_INCORRECT_SESSION_DATA and no task is created.

Header descriptions and every schema: Schemas. Machine-readable: openapi.json, openapi.yaml.