Senior Java Backend Developer

Overview

Job Title:

Senior Java Backend Developer (Java / Spring Boot / Microservices / Kafka).

Work Location:

Client – 3 days onsite per week (mandatory) downtown Calgary. Company:
Cogency.

Job Summary:

We are seeking a Senior Java Backend Developer with strong expertise in building scalable, high-performance enterprise applications. The ideal candidate will have deep hands-on experience in Java, Spring Boot, microservices architecture, and Kafka-based event-driven systems. This role focuses primarily on backend development, system design, performance optimization, and integration within a distributed environment.
Responsibilities   Design, develop, and maintain robust backend services using Java and Spring Boot
Develop and maintain RESTful APIs and microservices-based solutions
Build and support event-driven architectures using Kafka
Participate in architecture discussions and contribute to technical design decisions
Implement resilience, fault tolerance, and scalability best practices
Optimize application performance, memory usage, and database interactions
Write clean, maintainable, and well-documented code following coding standards
Perform unit testing, integration testing, and support QA/UAT cycles
Monitor, troubleshoot, and resolve production issues
Collaborate with Dev Ops, frontend teams, business analysts, and other stakeholders
Required Technical Skills   Core Java
Strong understanding of Object-Oriented Programming (OOP) principles
In-depth knowledge of Collections and Exception Handling
Hands-on experience with Java 8 features (Streams, Lambdas)
Solid understanding of Design Patterns
Knowledge of Garbage Collection and JVM memory management
Multithreading and concurrency concepts
Spring Boot & Backend Frameworks
Dependency Injection (DI) and Inversion of Control (IoC)
REST API development and best practices
Configuration management and environment handling
JPA / Hibernate for data persistence
Transaction management
Unit and integration testing (JUnit, Mockito)
Microservices Architecture
Service decomposition and domain-driven design principles
Inter-service communication (REST, messaging)
Resilience patterns (Circuit Breaker, Retry, Bulkhead)
Logging, monitoring, and distributed tracing (Observability)
API gateway and service discovery concepts
Kafka
Topics, Producers, and Consumers implementation
Consumer Groups and offset management
Kafka cluster architecture and replication
Message serialization (Avro/JSON)
Kafka monitoring, troubleshooting, and performance tuning
Database & Performance
Strong SQL skills and query optimization

Experience with relational databases (e.g., Oracle, SQL Server, Postgre

SQL)
Understanding of indexing and performance tuning
Qualifications   Bachelor’s degree in Computer Science, Engineering, or a related field
7+ years of hands-on backend development experience
Experience working in large-scale enterprise environments
Strong analytical, problem-solving, and debugging skills
Excellent communication and collaboration abilities

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