Building a Payment Processor: The Final One Percent

📰 Dev.to · Oreoluwa Bimbo-Salami

Learn to build a robust payment processor by implementing idempotency, message queues, and retries to handle the final one percent of edge cases

intermediate Published 7 May 2026

Action Steps

Implement idempotency in your payment processor to prevent duplicate transactions
Set up a message queue to handle asynchronous payments and retries
Configure retries with exponential backoff to handle temporary failures
Test your payment processor with edge cases to ensure robustness
Monitor and analyze payment processing logs to identify areas for improvement

Who Needs to Know This

Developers and engineers building payment processing systems can benefit from this knowledge to ensure reliability and accuracy in their systems

Key Insight

💡 Idempotency, message queues, and retries are crucial for building a robust payment processor that can handle edge cases and ensure reliability

Key Takeaways

Learn to build a robust payment processor by implementing idempotency, message queues, and retries to handle the final one percent of edge cases

I had idempotency, a message queue, and retries. I thought I was finally building something...