Java Technical Lead (System Design)

On behalf of our Client from the US, Mobilunity is looking for a Java Technical Lead

You will work on mission-critical backend systems powering a large-scale US e-commerce platform. The role involves designing and developing backend services, integrations, inventory synchronization, order processing, pricing logic, and marketplace integrations supporting a high-traffic online business.

This is not a typical feature-delivery role. You’ll participate in architectural discussions, solve complex engineering problems, and collaborate directly with technical and business stakeholders to deliver scalable solutions.

Candidates must be available to work primarily during US business hours, with a preferred schedule of 1:00 PM – 8:00 PM CET.

What we’re looking for:

We’re looking for more than a Senior Java Developer.

We need an engineer who enjoys understanding business problems before proposing technical solutions.

You should be comfortable working with open-ended challenges, evaluating trade-offs, asking the right questions, and independently designing scalable backend solutions.

The ideal candidate:

thinks beyond implementation;

understands business impact;

enjoys solving complex engineering problems;

proactively identifies bottlenecks;

can justify architectural decisions;

understands scalability, performance and cost optimization;

uses AI as an engineering productivity tool while applying independent judgment.

Responsibilities:

Design, develop and maintain scalable backend services using Java and Spring.

Build integrations with internal services, marketplaces and external partners.

Develop REST and SOAP APIs.

Work on inventory synchronization, pricing, catalog management and order processing.

Participate in architecture discussions and technical decision-making.

Troubleshoot production issues.

Collaborate directly with engineering and business stakeholders.

Improve system scalability, reliability and performance.

Contribute to engineering standards and development best practices.

Requirements:

7+ years of commercial Java experience.

Strong Java SE and OOP knowledge.

Spring Boot, Spring Framework.

Hibernate/JPA.

REST APIs.

SOAP.

SQL (MySQL or similar).

Software architecture principles.

Experience designing scalable backend systems.

Strong analytical and problem-solving skills.

Advanced English.

Nice to have:

SAP Commerce (Hybris)

AWS

Docker

Kafka

CI/CD

GraphQL

Marketplace integrations

Event-driven architecture

High-load systems

Automotive / Retail / E-commerce

AI-assisted development

Experience working with US companies

In return we offer:

The friendliest community of like-minded IT-people

Open knowledge-sharing environment – exclusive access to a rich pool of colleagues willing to share their endless insights into the broadest variety of modern technologies

Mobilunity Medical Insurance program designed to attend our teams’ needs

Paid vacations and sick leaves, including 5 paid days per year that don’t require a sick note

Perfect office location in the city-center (900m from Lukyanivska metro station with a green and spacious neighborhood) or remote mode engagement: you can choose a convenient one for you, with a possibility to fit together both

No open-spaces setup – separate rooms for every team’s comfort and multiple lounge and gaming zones

English classes in 1-to-1 & group modes with elements of gamification

Neverending fun: sports events, tournaments, music band, multiple affinity groups

Come on board, and let’s grow together!