Docs

API reference

Use the OneForCaptcha REST API to submit a CAPTCHA and read back the solved token. Authenticate programmatic calls with an API key you create in the dashboard.

Authentication

Programmatic requests are authenticated with an API key. Create one from API keys in your dashboard. Send it in the X-API-KEY request header — this is the only accepted method.

X-API-KEY: ofc_live_xxx

Never put your API key in a URL (e.g. ?api-key=...) — query strings are written in plain text to server access logs, proxy logs, and browser history, and are the single most common way API keys leak. Query parameter authentication is not supported: a request that sends the key only as ?api-key=... is rejected with 400 Bad Request.

Base URL

https://oneforcaptcha.com

POST/createTask

Submits a CAPTCHA for solving and holds its price (hold) from your balance. Returns a task id you poll with /getTaskResult.

Parameter	Required	Description
X-API-KEY	Yes	Customer key — request header, never a URL parameter
type	Yes	image_to_text \| recaptcha_v2 \| recaptcha_v3 \| recaptcha_enterprise \| hcaptcha \| funcaptcha \| geetest \| turnstile \| aws_waf \| datadome
site_key	No	The site’s captcha widget key, when applicable (e.g. reCAPTCHA, hCaptcha, Turnstile)
site_url	No	The page URL where the captcha is served

curl -X POST "https://oneforcaptcha.com/createTask" \
  -H "X-API-KEY: $KEY" \
  -d '{"type":"recaptcha_v2","site_key":"6Le...","site_url":"https://example.com"}'

# 200
{ "task_id": "task_a1b2c3" }

GET/getTaskResult

Returns the current status of a task. Poll every 2–5 seconds until status is "ready". The charge is captured only once the captcha is solved; if it fails or expires, the hold is released.

Parameter	Required	Description
X-API-KEY	Yes	Customer key — request header, never a URL parameter
task_id	Yes	The id returned by /createTask

curl "https://oneforcaptcha.com/getTaskResult?task_id=task_a1b2c3" -H "X-API-KEY: $KEY"

# 200 (still working)
{ "status": "processing", "solution": null }

# 200 (solved)
{ "status": "ready", "solution": "03AGdBq26…" }

GET/getBalance

Returns your current prepaid balance.

Parameter	Required	Description
X-API-KEY	Yes	Customer key — request header, never a URL parameter

curl -H "X-API-KEY: $KEY" "https://oneforcaptcha.com/getBalance"

# 200
{ "balance": 42.50, "currency": "USD" }

Dashboard API

Wallet, transaction history, key management and billing endpoints live under /api/v1/* and are authenticated with the session cookie plus a CSRF token.