how-to-solve-recaptcha-invisible-using-api

reCAPTCHA Invisible — CaptchaAI Example Pack

Full working example for solving reCAPTCHA Invisible using the CaptchaAI API.

reCAPTCHA Invisible works without a visible checkbox — it activates automatically on form submission or via a programmatic grecaptcha.execute() call. This example sends the sitekey, page URL, and invisible=1 flag so the API returns a valid g-recaptcha-response token.

Languages: Python, Node.js, PHP, Go, Java, C#, Ruby, Rust, Kotlin, Bash

Related article

This example accompanies the blog article: How to Solve reCAPTCHA Invisible Using API

Prerequisites

• A CaptchaAI account with API key (get one here)
• A target page with reCAPTCHA Invisible for testing
• One or more of: Python 3.8+, Node.js 16+, PHP 8.0+, Go 1.21+, Java 11+, .NET 8+, Ruby 3.0+, Rust 1.70+, Kotlin 1.9+, or Bash with curl and jq

Setup

1. Clone the repository:

   git clone https://github.com/CaptchaAI/CaptchaAI-Examples.git
   cd CaptchaAI-Examples/articles/how-to-solve-recaptcha-invisible-using-api

2. Copy the environment file and add your credentials:

   cp .env.example .env

3. Edit .env with your API key and the target page's sitekey and URL.

4. Follow the language-specific setup below.

Python

cd python
pip install -r requirements.txt
python solve.py

Node.js

cd node
npm install
node solve.js

PHP

cd php
composer install
php solve.php

Go

cd go
go run solve.go

Java

cd java
javac Solve.java
java Solve

C#

cd csharp
dotnet run

Ruby

cd ruby
ruby solve.rb

Rust

cd rust
cargo run

Kotlin

cd kotlin
kotlinc solve.kt -include-runtime -d solve.jar
java -jar solve.jar

Bash

cd bash
chmod +x solve.sh
./solve.sh

Configuration

Variable	Description	Required
CAPTCHAAI_API_KEY	Your CaptchaAI API key (32 characters)	Yes
CAPTCHA_SITEKEY	reCAPTCHA Invisible sitekey from the target page	Yes
CAPTCHA_PAGEURL	Full URL of the page with reCAPTCHA	Yes
POLL_INTERVAL	Seconds between poll requests (default: 5)	No
MAX_TIMEOUT	Maximum seconds to wait for solution (default: 120)	No

How it works

1. Submit — Sends the CAPTCHA parameters to https://ocr.captchaai.com/in.php using method userrecaptcha with invisible=1
2. Wait — Pauses 15 seconds for initial processing
3. Poll — Checks https://ocr.captchaai.com/res.php every 5 seconds for the result
4. Result — Returns the solved token ready for injection into g-recaptcha-response

Expected output

[*] Submitting reCAPTCHA Invisible task...
[+] Task submitted. ID: 71234567
[*] Waiting 15s before first poll...
[*] Polling for result (attempt 1)...
[*] Not ready yet, waiting 5s...
[*] Polling for result (attempt 2)...
[+] Solved! Token: 03AHJ_Vuve5Asa4koK3KSMyUkCq0vUFCR5Im4CwB7PzO3...
[+] Full token length: 280 characters

Next step: inject this token via the page's data-callback function
or set the g-recaptcha-response hidden field and submit the form.

Common errors

Error	Cause	Fix
ERROR_WRONG_USER_KEY	API key is invalid or wrong format	Check your key at https://captchaai.com/dashboard
ERROR_KEY_DOES_NOT_EXIST	API key not found	Verify the key exists in your dashboard
ERROR_ZERO_BALANCE	No balance remaining	Top up your account balance
ERROR_CAPTCHA_UNSOLVABLE	CAPTCHA could not be solved	Verify sitekey and page URL are correct
CAPCHA_NOT_READY	Solution still processing	This is normal — keep polling
ERROR_BAD_TOKEN_OR_PAGEURL	Wrong sitekey + URL combination	Extract the correct sitekey from the target page

Troubleshooting

Script exits immediately with auth error

• Verify your API key is exactly 32 characters
• Make sure .env file is in the articles/how-to-solve-recaptcha-invisible-using-api/ directory (not inside a language folder)

Polling times out after 120 seconds

• The CAPTCHA may be unusually complex — try increasing MAX_TIMEOUT
• Check that the sitekey and page URL are correct for the target page
• Verify your account has sufficient balance

Token received but form submission fails

• The token may have expired (tokens are valid for ~120 seconds)
• Make sure you are injecting the token into the g-recaptcha-response hidden field
• Some invisible reCAPTCHAs use a data-callback function — call it with the token instead
• Some sites require additional cookies or headers alongside the token

API documentation

• CaptchaAI API Docs

Related examples

• CaptchaAI Quickstart — Your first solve in 5 minutes
• reCAPTCHA v2 Example — Checkbox reCAPTCHA solving
• reCAPTCHA v3 Example — Standard reCAPTCHA v3 solving
• reCAPTCHA v2 Enterprise Example — Enterprise v2 solving
• reCAPTCHA v3 Enterprise Example — Enterprise v3 solving
• Browse more examples in the CaptchaAI-Examples repository