Handling Error Responses

{
  "type": "https://errors.example.com/insufficient-funds",
  "title": "Insufficient Funds",
  "status": 402,
  "detail": "Account balance $5.00 is less than required $25.00",
  "instance": "/v1/payments/p_abc123",
  "balance": 5.00,
  "required": 25.00,
  "request_id": "req_xyz789"
}

error_page 404 /errors/404.json;
error_page 502 503 504 /errors/upstream.json;
location ~ ^/errors/ { internal; root /etc/nginx; }

int attempt = 0;
while (attempt < maxRetries) {
  Response r = call();
  if (r.status < 500 && r.status != 429) return r;
  int baseMs = (int) Math.min(30000, 100 * Math.pow(2, attempt));
  int sleep = ThreadLocalRandom.current().nextInt(baseMs / 2, baseMs);
  Thread.sleep(sleep);
  attempt++;
}