Senior Java Engineer - 80% Onsite - Java Greenfield - Micronaut/Netty

Tech Talent ID; Greater London; On-site; GBP 90,000 - 120,000; Full time

Job summary

Tech Talent ID is seeking a Senior Java Engineer to transform the tech stack, drive design, build and deliver greenfield services, and mentor a small team transitioning to Java. You will lead the shift from Legacy code to modern JVM technologies, establish reference architectures, and guide the engineering group.

The role focuses on modern Java (Java 25), Micronaut, Netty, PostgreSQL via JDBI, HEXagonal architecture, DDD, and RabbitMQ messaging, with production ownership and mentorship of .NET

Qualifications

• Strong ownership of production JVM systems and relational databases.
• Reliable messaging experience (idempotency, at-least-once delivery).
• Robust testing ethos (Testcontainers, ArchUnit).
• Mentoring mindset to upskill .NET engineers moving to Java.

Responsibilities

• Drive design, build and delivery of greenfield services.
• Lead the shift from Legacy code to modern JVM technologies.
• Establish reference architectures for the team.
• Mentor a transitioning engineering group.

Skills

Java

JVM systems

Micronaut

Netty

Domain-Driven Design

RabbitMQ

PostgreSQL

Testcontainers

ArchUnit

Mentoring

Tools

ArchUnit

Testcontainers

JDBI

Job description

Senior Java Engineer is required by this international distribution provider as they transform their tech stack and need someone to drive this across design, build and deliver greenfield services, whilst mentoring a small team as they cross-train into Java. You will lead the shift from Legacy code to modern JVM technologies, establish reference architectures, and mentor a transitioning engineering team.

The Tech Stack & Methodology includes -

• Modern Java (Java 25), Micronaut, Netty, and PostgreSQL (JDBI/No ORM)
• Hexagonal architecture, Domain-Driven Design (DDD), and RabbitMQ messaging
• Complete production-scope ownership with cutting-edge AI coding agents

Ideally you can demonstrate a background in -

• Deep engineering judgment: strong ownership of production JVM systems and relational databases
• Reliable messaging experience (idempotency, at-least-once delivery)
• Robust testing ethos (Testcontainers, ArchUnit)
• Mentoring mindset to upskill .NET engineers moving to modern, idiomatic Java

Please note, this has a requirement to be in the office four days per week,