● Develop a data operations platform that ingests data from various sources, transforms and processes the data, and then persists the result into various destinations. Built on top of Apache Kafka Connect and Stream.

● Develop highly-loaded server-side Java applications to retrieve big data from different sources (Apache Kafka, continuously updated file system), process and store data into different databases (Cassandra, Elasticsearch, Redis/KeyDb, PostgreSQL)● Develop REST API for data retrieval from those databases with subsequent filtering, aggregating and processing by user request● Develop microservices that communicate through the REST API or direct network messages (Netty, Google Protocol Buffers)● Design database schemas to store and query data in the most efficient way:⠀► Decreased Cassandra database load, improved query performance and system resilience by tuning compaction strategies, optimizing table structures, enhancing partition and clustering keys, revising the data storage approach and data retrieval strategies⠀► Improved Elasticsearch data indexing and retrieval by optimizing indices schema and queries structure. Reduced Elasticsearch disk utilization approximately 10 times by tuning data analyzers⠀► Drastically reduced search and tasks execution time by introducing caches (Redis, Guava, common maps) and preserving intermediate results on different levels of business logic● Research and design features, revise system micro and macro architecture, populate and plan Jira tasks, define implementation requirements, review code and provide feedback on improvements● Prepare and verify product PoC versions⠀► Significantly reduced Kafka consumer applications requirements by making code execution asynchronous (without loosing the reliability), tuning databases (Cassandra, Kafka) connection options, minimizing the size of transferred and stored data, so that allowed to handle production load of ~150k Kafka messages/sec and ~300k Cassandra updates per sec in a comparatively small deployment.⠀► Enhanced the development process by introducing Gradle and Nexus Sonatype to the company, unifying build logic, designing project build approach and development pipelines