Senior Java Backend Engineer: Real-Time Trading APIs

Ubique Systems; Kraków; On-site; PLN 180,000 - 280,000; Full time

Job summary

Ubique Systems in Kraków is seeking an senior software engineer to design, build, and optimize Java Spring Boot microservices for order and trade workflows. You will implement REST/GraphQL APIs, integrate with Kafka/ActiveMQ, and drive real-time data processing across AWS serverless stacks.

The role requires 8+ years in Java, experience with databases like PostgreSQL/MongoDB, and strong testing, CI/CD, and collaboration skills in an Agile environment.

Qualifications

• 8+ years of hands-on Java software engineering in large-scale environments.
• Bachelor’s or Master’s degree in Computer Science, Engineering, or related field.
• Experience building scalable Java microservices with Spring Boot and designing REST/GraphQL APIs.
• Experience with event-driven messaging using Kafka and ActiveMQ.
• Experience delivering through CI/CD pipelines and automated testing.
• Experience with GenAI/LLM app development (RAG, vector DBs, Spring AI).

Responsibilities

• Design, build, and enhance Java Spring Boot microservices and APIs.
• Build event-driven integrations using Kafka/ActiveMQ for real-time flows.
• Develop AWS serverless solutions and manage data in PostgreSQL and MongoDB.
• Apply CI/CD, secure SDLC, and automated testing with JUnit/Mockito.
• Optimize performance of low-latency, high-throughput services.
• Develop GenAI/LLM capabilities (RAG, vector DBs, Spring AI).
• Collaborate with Product Owners, Architects, and engineers; participate in code reviews.
• Apply DevOps practices: monitoring, logging, operational readiness.
• Support modernization toward cloud-native architectures.

Skills

Java

Spring Boot

Microservices

REST APIs

GraphQL

Kafka

ActiveMQ

AWS

Lambda

API Gateway

S3

DynamoDB

PostgreSQL

MongoDB

JUnit

Mockito

GenAI/LLM

RAG

Spring AI

Agile

Collaboration

Communication

Education

Bachelor’s or Master’s degree in Computer Science or related field

Tools

Kafka

ActiveMQ

AWS

CloudFormation

PostgreSQL

MongoDB

JUnit

Mockito

Spring Boot

Spring MVC

Spring Data

GenAI tooling

Job description

Ubique Systems in Kraków is seeking an senior software engineer to design, build, and optimize Java Spring Boot microservices for order and trade workflows. You will implement REST/GraphQL APIs, integrate with Kafka/ActiveMQ, and drive real-time data processing across AWS serverless stacks.

The role requires 8+ years in Java, experience with databases like PostgreSQL/MongoDB, and strong testing, CI/CD, and collaboration skills in an Agile environment.