Developer Confluent Kafka

Developer – Confluent Kafka (8+ years)

Experience gate: 8+ years total IT experience, with at least 4+ years hands-on on Kafka/Confluent Platform in development roles (not admin or ops only).

Mandatory skills

1. Java (Core + Kafka client APIs). Strong Java with hands-on Producer/Consumer API work. The candidate should understand idempotent producers, transactions, exactly-once vs at-least-once semantics, offset management and consumer groups. Spring Kafka is a plus.
2. Kafka Streams (KStream/KTable). Has built and run stream applications in production, covering stateful operations, joins, windowing, state stores and interactive queries.
3. ksqlDB / KSQL. Has written streams, tables and persistent queries, and promoted them across environments.
4. Kafka Connect, including custom connector development. Has built custom Source/Sink connectors with the Connect API and written Single Message Transforms (SMTs). Has also configured and deployed out-of-the-box connectors. This is the main differentiator from a generic Kafka developer, because the JD asks for custom adaptors and connectors.
5. Performance tuning. Has hands-on tuned producer, consumer and connector configurations (batching, linger, compression, fetch and poll settings) and partition and key strategy. Has diagnosed consumer lag and throughput or latency issues on Confluent clusters.
6. Security implementation at application level. Has configured SASL/SCRAM or OAuth, SSL/mTLS, ACLs and Confluent RBAC in client applications and connectors, plus encryption of data in transit and at rest.
7. Schema Registry and serialization. Has used Avro and/or Protobuf/JSON Schema with Confluent Schema Registry in producers, consumers and connectors.
8. Deployment scripting and environment promotion. Has scripted promotion of topics, connectors, streams and ksqlDB queries to production using shell and/or Python, the Confluent CLI and the Connect/ksqlDB REST APIs. Has worked with at least one CI/CD tool, such as Jenkins, GitLab CI or Azure DevOps.
9. Monitoring and troubleshooting. Has used Confluent Control Center, JMX metrics and logs to debug rebalances, lag, poison-pill messages and dead letter queues (DLQs).
10. Testing and release support. Has written unit tests for Kafka code (TopologyTestDriver, Embedded Kafka or Testcontainers) and has supported SIT, UAT, Staging and Go-Live releases. Comfortable on Linux.