public class SanjeeviKumar {

    String  role     = "Software Engineer @ Mettler-Toledo International";
    String  location = "Coimbatore, Tamil Nadu, India 🇮🇳";
    String  focus    = "Backend Systems · Platform Modernization · Cloud-Native";

    String[] currentlyDoing = {
        "Modernizing legacy Java microservices to Java 21 in production",
        "Designing Kafka-based event-driven architectures",
        "Mentoring backend developers at Spotknack (part-time)",
        "Building open-source tools for enterprise migration patterns"
    };

    String[] openTo = {
        "Backend / Microservices Engineer roles (2-3 YOE)",
        "Interesting distributed systems problems",
        "Technical discussions around cloud-native architecture"
    };
}

Languages

Frameworks & Libraries

Infrastructure & Messaging

Databases & Tools

Enterprise API Gateway for zero-downtime legacy-to-microservice migration using the Strangler Fig pattern

Built on Spring Cloud Gateway + WebFlux, this gateway sits in front of both legacy and modern systems and intelligently shapes traffic during migration.

Key capabilities:

• ⚖️ Weighted canary routing — shift traffic percentage between legacy and modern via environment variables, no redeployment needed
• 👻 Shadow traffic mirroring — async fire-and-forget duplication of requests to modern service for production load testing
• 🔐 Edge OAuth2/OIDC security — JWT validation via Keycloak at the gateway, abstracting auth from downstream services
• 🚦 Redis-backed rate limiting — distributed Token Bucket protecting legacy systems from spikes
• 📊 Kafka telemetry — real-time routing events, latency, and status codes streamed to Kafka

Java 21 Spring Cloud Gateway Kafka Redis Keycloak Docker Kubernetes Helm

• 🔭 Spring Cloud Gateway — advanced filter patterns, reactive routing internals
• 🌱 Event-driven architecture — exactly-once semantics, Kafka Streams
• ⚙️ Platform engineering — GitOps, Helm chart design, multi-environment Kubernetes deployments
• 📖 Distributed systems — CAP theorem, consensus algorithms, fault tolerance patterns

Part-time backend mentor helping students break into the industry. I cover:

• Java fundamentals → Spring Boot → REST API design
• Microservices architecture patterns
• Test-driven development with JUnit & Mockito
• Real-world backend engineering practices

If you're learning backend development and want guidance, feel free to reach out.