Design, implement, and maintain enterprise database systems (SQL Server, Oracle, DB2, MySQL, PostgreSQL) and modern/NoSQL platforms (MongoDB, Cosmos DB, DynamoDB, Elasticsearch); ensure performance, security, and high availability. Install, configure, and manage middleware platforms (WebLogic, JBoss, Tomcat, WebSphere, IIS, MQ, Node.js, etc.) Monitor, troubleshoot, and optimize application server environments; ensure middleware security, patching, and compliance.