API Endpoints

Complete reference for all available API endpoints. HTTPS only, standard JSON responses.

Base URL

text 
https://captchakings.com/api/

POST /process.php

Process and solve a CAPTCHA image.

Request

Parameter Type Required Description
captcha File ✅ Yes CAPTCHA image file (JPG, PNG, GIF, max 5MB)
api_key String ⚠️ Optional API key (if not in header)

Headers

Header Value Required
Authorization Bearer {api_key} ✅ Recommended
X-API-Key {api_key} ⚠️ Alternative
Content-Type multipart/form-data ✅ Auto

Response (Success)

json 
{
  "success": true,
  "data": {
    "type": "text",
    "prediction": "GXL4",
    "confidence": "89.79%",
    "type_confidence": "100.00%",
    "process_time": 1.4,
    "timestamp": "2025-11-05 23:54:50"
  },
  "billing": {
    "amount_charged": "0.000800",
    "balance_remaining": "0.499200",
    "plan": "free_trial"
  },
  "processing_time": "1.4s",
  "mode": "api_key",
  "message": "CAPTCHA processed successfully"
}

Response (Error)

json 
{
  "success": false,
  "error": "Invalid API key or account inactive"
}

Response Fields

Field Type Description
success Boolean Request success status
data.prediction String Solved CAPTCHA text
data.confidence String Prediction confidence (%)
data.process_time Float Processing time in seconds
billing.amount_charged String USD charged this request
billing.balance_remaining String Remaining USD balance (-1 = unlimited)
mode String api_key or free_trial

HTTP Status Codes

Code Meaning
200 Success - CAPTCHA solved
400 Bad Request - Invalid input or error
401 Unauthorized - Invalid API key
403 Forbidden - Insufficient credits
405 Method Not Allowed - Use POST
429 Too Many Requests - Rate limit exceeded
500 Server Error - Internal error

POST /api/recaptcha.php NEW

Solve Google reCAPTCHA 3x3 Tile Grid (classification) and 4x4 YOLO Grid (instance segmentation) challenges. See full guide at reCAPTCHA Solver Documentation.

Request Parameters

Parameter Type Required Description
grid String ⚠️ Optional "3x3" (default) or "4x4"
image_base64 String / File ✅ Yes Base64 encoded image string or file upload (image)
challenge_title String ✅ Yes Challenge instruction text (e.g. "traffic lights", "crosswalks", "bus")
focus_tiles Array ⚠️ Optional Array of tile numbers (e.g. [0, 4, 8]) to re-evaluate on dynamic replacement images
api_key String ⚠️ Optional CaptchaKings API key (if not sent via Bearer / X-API-Key header)

Response (Success)

json 
{
  "success": true,
  "type": "recaptcha_3x3",
  "grid": "3x3",
  "tiles_to_click": [0, 1, 4],
  "num_detections": 3,
  "challenge_title": "traffic lights",
  "confidence": 0.985,
  "processing_time": "0.182s",
  "billing": {
    "amount_charged": "0.001000",
    "balance_remaining": "9.999000",
    "plan": "professional"
  },
  "message": "reCAPTCHA 3x3 challenge solved successfully"
}