Checkpointing in message processing ensures that systems can recover from failures without losing track of their progress. The author starts by drawing an analogy between video games and business processes. Just as games used checkpoints to allow players to save their progress and avoid starting over, businesses need a method to track their message processing status. This is particularly important in systems that rely on message-based communication, where losing track of messages can lead to inconsistencies and errors. The article details the Outbox pattern, which combines the storage of messages with transaction updates to maintain data integrity. By using a relational database like PostgreSQL, messages are stored alongside their transaction IDs, ensuring that all parts of the system are in sync. The author presents SQL queries that facilitate polling for messages while maintaining a global order, addressing the balance between performance and reliability. To implement checkpointing, a separate table for storing processor checkpoints is proposed, allowing systems to remember their last processed message. The author explains a stored procedure designed to manage these checkpoints, detailing how it handles updates and insertions while checking for position mismatches. This approach avoids common pitfalls in production environments, emphasizing the need for careful management of state and error handling. The complexity of the procedure reflects the challenges faced in real-world applications, where reliability and consistency are paramount.