In my previous role, I worked on a large-scale financial system that required real-time processing of transactions. One major challenge was ensuring data consistency across multiple databases. I implemented a distributed locking mechanism using Redis to manage concurrent access and prevent race conditions. This solution improved system reliability and reduced transaction errors by 20%.

I start by isolating the issue using logging and monitoring tools to identify the root cause. Once identified, I use a systematic approach to debug, often starting with the most recent changes. I also leverage unit tests and integration tests to validate fixes. If the issue is complex, I may involve other team members for a fresh perspective.

I focus on optimizing both the code and the system architecture. For code, I use profiling tools to identify bottlenecks and apply techniques like caching, lazy loading, and asynchronous processing. For the architecture, I consider load balancing, database indexing, and scaling strategies. Regular performance testing helps me validate improvements and ensure the system meets performance targets.

Security is a top priority. I follow best practices such as input validation, secure coding standards, and regular code reviews. I also implement encryption for sensitive data and use role-based access control. Additionally, I stay updated on security threats and vulnerabilities, and I conduct regular security audits and penetration testing to identify and mitigate risks.

I have extensive experience with Git, using it for branching, merging, and managing code changes. I follow a feature branch workflow, where each feature or bug fix is developed in a separate branch. This allows for isolated development and easy rollback if needed. I also use pull requests for code reviews, ensuring that changes are reviewed and tested before merging into the main branch.