How to integrate it in your plugin (Java)

This is the part you have to code yourself inside your plugin — the store generates and manages the keys, but whether the plugin works or not is decided by your own code.

API contract

POST https://store.iiaan.dev/api/license/validate
Content-Type: application/json

{
  "licenseKey": "AB12CD-EF34GH-IJ56KL-MN78OP",
  "serverIdentifier": "123.45.67.89",
  "version": "1.4.2"
}

Response if valid:

{ "valid": true, "plugin": "ZenStaff" }

Response if not (revoked key, IP outside whitelist, or the license already reached its server limit):

{ "valid": false, "message": "This server is not in the whitelist" }

Example Java class

Uses HttpClient, included since Java 11, no external dependencies:

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.charset.StandardCharsets;
import java.util.Properties;
import java.io.InputStream;

public class LicenseChecker {

    private static final String VALIDATE_URL = "https://store.iiaan.dev/api/license/validate";

    /** Calls store.iiaan.dev's API to check this server's license. */
    public static boolean checkLicense(String serverIdentifier, String pluginVersion) {
        try {
            // 1. Read license.properties — it's bundled inside the jar itself
            //    (the store injects it automatically on download, don't edit it by hand)
            Properties props = new Properties();
            try (InputStream in = LicenseChecker.class.getResourceAsStream("/license.properties")) {
                if (in == null) {
                    System.out.println("[License] license.properties not found in the jar.");
                    return false;
                }
                props.load(in);
            }

            String licenseKey = props.getProperty("license-key");

            // 2. Call the validation API
            String json = String.format(
                "{\"licenseKey\":\"%s\",\"serverIdentifier\":\"%s\",\"version\":\"%s\"}",
                licenseKey, serverIdentifier, pluginVersion
            );

            HttpClient client = HttpClient.newHttpClient();
            HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(VALIDATE_URL))
                .header("Content-Type", "application/json")
                .POST(HttpRequest.BodyPublishers.ofString(json, StandardCharsets.UTF_8))
                .build();

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

            return response.statusCode() == 200 && response.body().contains("\"valid\":true");

        } catch (Exception e) {
            System.out.println("[License] Could not validate: " + e.getMessage());
            return false; // you decide whether a network failure blocks the plugin or lets it through
        }
    }

    /** Optional: auto-detects the server's public IP. */
    public static String getPublicIp() {
        try {
            HttpClient client = HttpClient.newHttpClient();
            HttpRequest request = HttpRequest.newBuilder(URI.create("https://api.ipify.org")).GET().build();
            HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
            return response.body().trim();
        } catch (Exception e) {
            return "unknown";
        }
    }
}

Usage inside your plugin

@Override
public void onEnable() {
    String serverIp = LicenseChecker.getPublicIp();
    boolean valid = LicenseChecker.checkLicense(serverIp, getDescription().getVersion());

    if (!valid) {
        getLogger().severe("Invalid license — disabling the plugin.");
        getServer().getPluginManager().disablePlugin(this);
        return;
    }

    getLogger().info("License valid ✓");
    // ... the rest of your startup logic
}

Recommendation

Don't validate only in onEnable(). Schedule a repeating task (e.g. every 6 hours with BukkitScheduler) to call checkLicense() again, so the "last seen" info in the panel stays accurate for servers that run for weeks without restarting.