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# Senior Back-end Developer

- **Company:** Fl3xx
Senior Back-end DeveloperFl3xx
- **Location:** Wien, Austria (Remote available)
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Java (Programming Language), Apache Tomcat, Relational Databases, Distributed Systems, Elasticsearch, Gradle, Hibernate (Java), Spring Framework, PostgreSQL, Apache Maven, Redis, Web Performance Optimization, Large Language Models, Concurrency, Backend, Git, Kotlin, Apache Kafka, Functional Programming
- **Published:** September 25, 2026
- **Apply:** https://devjobs.at/job/0c9357b9f4bfe01e0aa29bc957336af7

## About the Role

* Git, Maven, Spring, Hibernate, Tomcat, ElasticSearch, Redis, PostgreSQL, Gradle, Helidon, Kafka.
 * Deep know-how of high-performance web applications, relational databases, concurrency, distributed systems.
 * Team player leveraging your seniority and background to guide young developers to succeed.
 * You possess very good communication skills and the ability to cross-collaborate with different internal stakeholders.
 * You speak and write English fluently., * Brilliant Collaborator with 6+ years of development experience in extensive and complex Java projects.
 * Experience with functional programming in Java (libraries like Pragmatica-lite, Vavr, Cyclops or similar). Knowledge of Kotlin or Scala functional programming is a plus.
 * Experience with LLM agentic coding and optimisations for autonomous workflows.

## Description

* Apache Tomcat
 * Scala
 * Maven
 * Redis
 * Kotlin
 * Java
 * Git
 * Elasticsearch
 * PostgreSQL
 * Hibernate
 * Spring
 * Apache Kafka
 * Gradle, * We are looking for a Back-end Developer to join our Dev team and contribute to the design of our new software features with our international team!
 * Your job is to implement the systems specifications for our Java-based system with a sophisticated web-GUI, accompanied by mobile apps and various interfaces to external systems.
 * In your job you can build on a team of professionals who want to profit from your extensive experience.
 * Your work is focused on the implementation of well defined use cases in close cooperation with the customer and the product manager.
 * Technical requirements analysis, system design, and implementation.
 * Take full ownership of projects from design to deployment.
 * Write quality code, with no compromises on correctness and deterministic behaviour / failure handling / performance.
 * Web centric distributed scalable software development in Java.
 * Advocate for product quality within a cross-functional development team.
 * Lots of space for your own ideas and creations, flat hierarchies and very short decision making process.
 * Explore, create, tune and optimise LLM agentic workflows for engineering deliveries.


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