Java Examples

import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.ByteArrayOutputStream;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.time.Duration;

public class CaptchaKingsOcr {

    private static final String API_KEY = "YOUR_API_KEY";
    private static final String ENDPOINT = "https://captchakings.com/api/process.php";

    public static void main(String[] args) throws IOException, InterruptedException {
        Path image = Path.of("captcha.png");
        String boundary = "----CKBoundary" + System.currentTimeMillis();

        // Build multipart body manually (no external libs needed)
        ByteArrayOutputStream body = new ByteArrayOutputStream();
        byte[] fileBytes = Files.readAllBytes(image);
        String head = "--" + boundary + "\r\n"
                + "Content-Disposition: form-data; name=\"captcha\"; filename=\"captcha.png\"\r\n"
                + "Content-Type: image/png\r\n\r\n";
        body.write(head.getBytes(StandardCharsets.UTF_8));
        body.write(fileBytes);
        body.write(("\r\n--" + boundary + "--\r\n").getBytes(StandardCharsets.UTF_8));

        HttpClient client = HttpClient.newBuilder()
                .connectTimeout(Duration.ofSeconds(10))
                .build();

        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(ENDPOINT))
                .timeout(Duration.ofSeconds(10)) // OCR p95 is 2.5s; 10s is safe
                .header("Authorization", "Bearer " + API_KEY)
                .header("Content-Type", "multipart/form-data; boundary=" + boundary)
                .POST(HttpRequest.BodyPublishers.ofByteArray(body.toByteArray()))
                .build();

        HttpResponse<String> response =
                client.send(request, HttpResponse.BodyHandlers.ofString());

        if (response.statusCode() == 200) {
            // With a JSON lib (Jackson/Gson) parse properly; quick extraction:
            String json = response.body();
            String prediction = json.replaceAll(".*\"prediction\"\\s*:\\s*\"([^\"]+)\".*", "$1");
            System.out.println("Solved: " + prediction);
        } else {
            // 4xx errors are never billed
            System.err.println("HTTP " + response.statusCode() + ": " + response.body());
        }
    }
}