Application Performance Engineer

Shoper is a leader in e-commerce solutions in Poland, providing a SaaS platform that supports businesses in online sales, payments, logistics, and marketing services. The IT team seeks an engineer responsible for ensuring the speed and performance of online stores built on the Shoper platform, focusing on identifying and resolving system bottlenecks.

• Expert knowledge of PHP, including request lifecycle, memory management, OPcache, and profiling.
• Experience with MySQL / Percona XtraDB Cluster: query analysis with EXPLAIN, understanding replication and clustering specifics.
• Proficiency with RabbitMQ for designing and debugging asynchronous flows: queues, exchanges, error handling, retries, dead-letter queues, and ensuring idempotency.
• Experience with Memcached caching strategies and debugging.
• Knowledge of Redis for session management.
• Familiarity with Elasticsearch for search, indexing, mapping, queries, and performance tuning.
• Ability to debug issues at the Nginx HTTP layer, a mandatory skill.

• Develop and enhance internal tools by adding new functionalities and refactoring existing code.
• Debug complex issues in PHP, including performance problems, memory leaks, race conditions, and service integration errors.
• Optimize and improve test processes for speed, stability, and coverage.
• Ensure high performance and reliability of the platform across application, database, queues, and caching layers.
• Scale existing processes to handle increased load.