CaptchaSonic Go SDK

Official Go SDK for the CaptchaSonic CAPTCHA solving API — gRPC binary transport (fastest) + HTTP/REST fallback.

Installation

go get github.com/Captcha-Sonic/captchasonic-go@latest

Or pinned to a specific version:

go get github.com/Captcha-Sonic/captchasonic-go@v1.0.0

Quick Start

package main

import (
    "context"
    "fmt"
    "log"
    "os"

    "github.com/Captcha-Sonic/captchasonic-go"
)

func main() {
    // Create client — gRPC binary transport (default, fastest)
    client, err := captchasonic.NewClient("sonic_your_api_key")
    if err != nil {
        log.Fatal(err)
    }
    defer client.Close()

    ctx := context.Background()

    // Check balance
    balance, _ := client.GetBalance(ctx)
    fmt.Printf("Balance: $%.4f\n", balance)

    // Solve CAPTCHA — images sent as raw binary (zero base64 overhead)
    imgBytes, _ := os.ReadFile("tile.png")
    resp, err := client.SolvePopularCaptcha(ctx, [][]byte{imgBytes},
        "Select all traffic lights", "objectClassify")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("Solution:", resp.TypedSolution.GetGrid().GetObjects())
}

Transports

Transport	Default	Speed	Images
gRPC	✅ yes	Fastest — binary, HTTP/2	Raw []byte
HTTP	no	Good — JSON REST	Auto base64-encoded

gRPC is the default. Pass WithHTTP() only if you specifically need the REST transport.

Configuration Options

// Production gRPC (default)
client, _ := captchasonic.NewClient("sonic_xxxx")

// HTTP/REST transport
client, _ := captchasonic.NewClient("sonic_xxxx", captchasonic.WithHTTP())

// Custom endpoint
client, _ := captchasonic.NewClient("sonic_xxxx",
    captchasonic.WithEndpoint("api.captchasonic.com:443"))

// Local development (insecure gRPC)
client, _ := captchasonic.NewClient("sonic_xxxx",
    captchasonic.WithEndpoint("localhost:50052"),
    captchasonic.WithInsecure())

// Advanced options
captchasonic.WithTimeout(45 * time.Second)
captchasonic.WithGRPCMsgSize(100 * 1024 * 1024) // 100 MB max message
captchasonic.WithHTTPPool(200, 200, 90*time.Second)

Solve Methods

PopularCaptcha

resp, err := client.SolvePopularCaptcha(ctx, images,
    "Select all traffic lights", "objectClassify",
    captchasonic.WithWebsite("https://example.com", "sitekey"))

ReCaptcha V2

resp, err := client.SolveRecaptchaV2(ctx, images, "traffic lights",
    captchasonic.WithQuestionType("split_33"),
    captchasonic.WithWebsiteURL("https://example.com"))

OCR (Image-to-Text)

// MtCaptcha
resp, err := client.SolveOcr(ctx, images,
    captchasonic.WithModule("mtcaptcha"),
    captchasonic.WithLengthRange(4, 6))

// BLS (numeric)
resp, err := client.SolveOcr(ctx, images,
    captchasonic.WithModule("bls"),
    captchasonic.WithNumeric())

Geetest

// Nine-grid
resp, err := client.SolveGeetest(ctx, "nine", "the bear",
    captchasonic.WithImages(tiles))

// Slide
resp, err := client.SolveGeetest(ctx, "slide", "",
    captchasonic.WithImages(puzzle),
    captchasonic.WithExamples(piece))

// Click
resp, err := client.SolveGeetest(ctx, "click", "the bear",
    captchasonic.WithImages(tiles))

TikTok (type-based)

resp, err := client.SolveTikTok(ctx, "whirl", "Rotate to match", images,
    captchasonic.WithExamples(examples))

resp, err := client.SolveTikTok(ctx, "click", "Select shape", images)
resp, err := client.SolveTikTok(ctx, "slide", "", images)

Binance (type-based)

resp, err := client.SolveBinance(ctx, "grid", "Select the bicycle", images)
resp, err := client.SolveBinance(ctx, "slide", "", images)

AWS WAF

resp, err := client.SolveAwsWaf(ctx, images, "Select all squares",
    captchasonic.WithWebsiteURL("https://example.com"))

Turnstile (token task — auto-polls)

resp, err := client.SolveTurnstile(ctx, "https://example.com", "0x4AAAAAAA")

Other Token Tasks

// Cloudflare (proxy REQUIRED)
client.SolveCloudflare(ctx, url, key, "http://user:pass@host:1080")

// reCAPTCHA v2/v3 token
client.SolveRecaptchaV2Token(ctx, url, key, captchasonic.WithProxyless())
client.SolveRecaptchaV3Token(ctx, url, key, captchasonic.WithProxy("..."))

// PopularCaptcha token (PopularCaptcha browser automation)
client.SolvePopularCaptchaToken(ctx, url, key, captchasonic.WithProxyless())

Task Option Helpers

captchasonic.WithImages(imgs)              // set images via option
captchasonic.WithExamples(exampleImages)   // reference images
captchasonic.WithScreenshot()              // enable screenshot
captchasonic.WithWebsite(url, key)         // billing: websiteUrl + websiteKey
captchasonic.WithWebsiteURL(url)           // billing: websiteUrl only
captchasonic.WithQuestionType(qt)          // e.g. "objectDrag", "split_33"
captchasonic.WithProxy("http://...")       // proxy for token tasks
captchasonic.WithProxyless()               // proxyless variant
captchasonic.WithModule("bls")             // OCR module
captchasonic.WithNumeric()                 // OCR: digits only
captchasonic.WithCaseSensitive()           // OCR: case sensitive
captchasonic.WithLengthRange(3, 8)         // OCR: min/max text length
captchasonic.WithGeetestVersion(4)         // Geetest version

Error Handling

resp, err := client.GetBalance(ctx)
if err != nil {
    if sonicErr, ok := err.(*captchasonic.SonicError); ok {
        fmt.Printf("API error %d: %s\n", sonicErr.ErrorID, sonicErr.Message)
    }
}

Retries automatically on UNAVAILABLE, RESOURCE_EXHAUSTED, DEADLINE_EXCEEDED with exponential backoff (1s, 2s).

Validation

NewClient validates the API key format immediately — zero network calls:

• Must start with "sonic_"
• Minimum 12 characters

Per-task validation: images required/count/size, question required, proxy format.

Connection Pooling

• gRPC: Single grpc.ClientConn multiplexes all calls as HTTP/2 streams. Keep-alive pings every 10s. Create once, reuse across goroutines.
• HTTP: http.Transport with configurable MaxConnsPerHost (default 100).

License

MIT — see LICENSE.