## Getting Started

To access the API, you must authenticate and maintain a valid session.

1. **Authentication**
Most endpoints require cookie-based authentication.
Use the login endpoint with your KlickTipp username and password to obtain a **session cookie**, which must be sent with all subsequent requests.
2. **Request Preparation**
Replace all placeholder values such as email addresses, IDs, or timestamps with valid test data.
Invalid formats are a common source of errors.
3. **Response Handling**
The API returns structured payloads and numeric error codes.
Always validate HTTP status codes and response bodies programmatically.