Ship licensed software
in an afternoon.

const auth = await fetch(BASE + "/api/v1/license", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ appId, secret, key, hwid }),
}).then(r => r.json());

if (!auth.success) {
  // "HWID mismatch" · "License banned" · "License expired"
  return exit(auth.message);
}

const { session, license } = auth;
console.log("expires:", license.expires ?? "never");

// post() sends a nonce and verifies X-Signature (HMAC of your secret)
// so a spoofed server can never fake a "success" — see the API docs.
setInterval(async () => {
  const c = await post("/api/v1/check", { session });
  if (!c.success) exit("Session revoked");
}, 60_000);

import requests

auth = requests.post(BASE + "/api/v1/license", json={
    "appId": APP_ID, "secret": SECRET,
    "key": key, "hwid": hwid,
}).json()

if not auth["success"]:
    # "HWID mismatch" · "License banned" · "License expired"
    raise SystemExit(auth["message"])

session = auth["session"]
print("expires:", auth["license"]["expires"] or "never")

while True:
    time.sleep(60)
    c = requests.post(BASE + "/api/v1/check", json={"session": session}).json()
    if not c["success"]:
        raise SystemExit("Session revoked")

var auth = await Post("/api/v1/license", new { appId, secret, key, hwid });

if (!auth.success)
{
    // "HWID mismatch" · "License banned" · "License expired"
    MessageBox.Show((string)auth.message);
    return;
}

string session = auth.session;
Console.WriteLine($"expires: {auth.license.expires ?? "never"}");

var timer = new PeriodicTimer(TimeSpan.FromSeconds(60));
while (await timer.WaitForNextTickAsync())
{
    var c = await Post("/api/v1/check", new { session });
    if (!c.success) Environment.Exit(1);
}