🧩 Captcha – A Unified CAPTCHA Verification Library for Go

captcha is a modular, provider-agnostic CAPTCHA verification library for Go that makes it easy to validate challenge responses from Cloudflare Turnstile, Google reCAPTCHA, and hCaptcha using a unified interface.

It also includes optional Protobuf support for gRPC-based services.

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✨ Features

• ✅ Unified interface for multiple CAPTCHA providers
• 🔐 Secure server-side verification of challenge tokens
• 📦 Simple API for Go web and microservice backends
• 🔁 Optional Protocol Buffers integration for gRPC use cases
• 📚 Clean, testable, idiomatic Go

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📦 Installation

go get github.com/ja7ad/captcha

If you're using Protobuf/gRPC support:

go get github.com/ja7ad/captcha/proto

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🔐 Supported Providers

Provider	Enum	Notes
Cloudflare	captcha.ProviderCloudflare	Fast and privacy-respecting
Google reCAPTCHA	captcha.ProviderGoogle	Widely supported
hCaptcha	captcha.ProviderHcaptcha	Strong bot protection

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🚀 Quick Start

package main

import (
	"context"
	"fmt"
	"github.com/ja7ad/captcha"
)

func main() {
	c, err := captcha.New(captcha.ProviderCloudflare, "your-secret-key")
	if err != nil {
		panic(err)
	}

	success, err := c.Validate(context.Background(), "challenge-token-from-client")
	if err != nil {
		fmt.Println("Verification error:", err)
		return
	}

	if success {
		fmt.Println("CAPTCHA verified ✅")
	} else {
		fmt.Println("CAPTCHA failed ❌")
	}
}

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🔄 With Full Challenge Response

challenge, err := c.ValidateWithResponse(ctx, "challenge-token")
if err != nil {
	log.Fatal(err)
}

if challenge.Success {
	// do something
}

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🤝 Contributing

Pull requests, issues, and discussions are welcome!
Feel free to fork and enhance the library for your use case.