Application Performance Engineer

Grupa Shoper is a leader in e-commerce solutions in Poland, providing a SaaS platform that supports entrepreneurs with online stores, payments, logistics, and marketing services. The company helps thousands of businesses grow and offers a modern work environment with real impact on the product.

• Expert-level knowledge of PHP including request lifecycle, memory management, OPcache, and profiling.
• Experience with MySQL / Percona XtraDB Cluster including query analysis (EXPLAIN), replication, and cluster specifics.
• Proficiency with RabbitMQ for designing and debugging asynchronous flows, including queues, exchanges, error handling, retries, dead-letter queues, and idempotency.
• Knowledge of Memcached with cache invalidation strategies and debugging.
• Familiarity with Redis for sessions and Elasticsearch for search and indexing, including mappings, queries, and performance tuning.
• Ability to debug HTTP layer issues using Nginx.

• Develop internal tools by adding new features and refactoring existing code.
• Debug complex PHP problems including performance issues, memory leaks, race conditions, and service integration errors.
• Tune and improve testing processes to accelerate, stabilize, and increase test coverage in the pipeline.
• Maintain performance and reliability of the platform at the application, database, queue, and cache levels.
• Scale existing processes to handle increased load.