Senior Server-Side Engineer – Java / Kotlin

CSI GLOBAL LTD; Burgess Hill; Híbrido; GBP 70.000 - 110.000; Jornada completa

Descripción de la vacante

CSI GLOBAL LTD is seeking a Backend Engineer to design and operate server-side applications and distributed microservices in production. You will own RESTful APIs, event-driven data pipelines, and database interactions across SQL and NoSQL stores.

The role emphasizes defensive programming, comprehensive testing, and performance optimization to maintain enterprise reliability. Onsite work with some flexibility is required.

Formación

• Proven track record building and operating server-side applications and distributed microservices in production.
• Solid experience designing and consuming RESTful APIs and event-driven architectures with Apache Kafka.
• Hands-on database exposure across relational databases (e.g., PostgreSQL, Oracle, MySQL) or NoSQL data stores (e.g., MongoDB, Cassandra, DynamoDB); balanced exposure to both paradigms is highly valued.
• Experience with automated testing suites (unit, integration, regression) and modern CI/CD automation tools.
• Strong debugging, root-cause analysis, and performance optimization skills.

Responsabilidades

• Articulate and defend architectural decisions, balancing trade-offs between monolith vs microservices, REST vs GraphQL, and synchronous vs event-driven patterns.
• Ensure defense in depth with fault containment, strict input validation, and enterprise security standards.
• Maintain clean code fundamentals with high-signal automated tests and readable abstractions that support team velocity.

Conocimientos

Server-side development

Distributed microservices

REST APIs

Event-driven architectures

Performance optimization

Debugging

CI/CD automation

Testing (unit/integration)

Architectural decision making

Design reasoning

Herramientas

Apache Kafka

PostgreSQL

Oracle

MySQL

MongoDB

Cassandra

DynamoDB

Descripción del empleo

Burgess Hills, UK

Onsite to 3 days per week

We expect you to understand how your tools function beneath the syntax:

• Deep knowledge of runtime behavior (e.g., JVM memory model, garbage collection mechanics, thread pools, event loops, or coroutines).
• Clear mental models of networking, HTTP protocol mechanics, connection pooling, and serialization overhead.
• Concrete understanding of database internals (e.g., indexing mechanics, locking mechanisms, query execution plans, and transaction isolation levels).

2. Architecture & Deliberate Trade-Offs

You must be prepared to articulate and defend engineering decisions:

• Justify architectural choices: Monolith vs. Microservice, REST vs. GraphQL, synchronous RPC vs. event-driven pipelines.
• Weigh trade-offs across consistency, latency, network payload sizes, and developer ergonomics when designing client-facing data layers.
• Navigate database selection (relational SQL vs. NoSQL document/key-value stores) based on query patterns, access frequency, and data integrity guarantees.

3. Production-Grade Enterprise Reliability

Financial platforms require defense in depth and fault containment:

• Proactive defensive programming, strict input validation, data masking, and adherence to enterprise security standards.
• Resilient dependency management: zero cascading failures when downstream services degrade or fail.
• Clean code fundamentals: clear separation of concerns, high-signal automated tests, and readable abstractions that support team velocity.

Qualifications & Skills

Baseline Requirements

• Proven track record building and operating server-side applications and distributed microservices in production.
• Solid experience designing and consuming RESTful APIs and event-driven architectures with Apache Kafka.
• Hands-on database exposure across relational databases (e.g., PostgreSQL, Oracle, MySQL) or NoSQL data stores (e.g., MongoDB, Cassandra, DynamoDB); balanced exposure to both paradigms is highly valued.
• Experience with automated testing suites (unit, integration, regression) and modern CI/CD automation tools.
• Strong debugging, root-cause analysis, and performance optimization skills.

Preferred Technical Stack & Experience

• Legacy Modernization: Comfort diving into legacy enterprise codebases, identifying domain boundaries, and safely migrating functionality to modern services without downtime.

Relevant technologies that you may encounter: