Senior Backend Developer (Java / .NET)

Experis; Warszawa; Hybrid; PLN 150,000 - 190,000; Full time

Benefits offered by this job

Medicover healthcare package

Multisport card

Group life insurance

Job summary

Experis is seeking an experienced Backend Developer (Java or .NET) in Warsaw on a hybrid schedule (in-office 3 days a week). The role focuses on building scalable backend services and REST APIs powering client-facing portal applications.

Responsibilities include designing robust data integrations, containerized deployments with Docker/Kubernetes/OpenShift, and implementing CI/CD pipelines with automated testing. 8+ years of backend experience and strong SQL skills are required.

Qualifications

• 8+ years of backend development experience.
• Strong expertise in Java or .NET.
• Hands‑on experience building and consuming REST APIs.
• Experience with Docker, Kubernetes, or OpenShift.
• Solid SQL and database knowledge.
• Experience with CI/CD pipelines and automated testing.

Responsibilities

• Develop and maintain backend services and REST APIs.
• Design and integrate solutions with relational and NoSQL databases.
• Collaborate with frontend teams for seamless integrations.
• Build and deploy applications in containerized environments.
• Implement secure coding practices, automated testing and CI/CD pipelines.
• Optimize performance, scalability and reliability.
• Troubleshoot production issues and support stability.
• Participate in Agile ceremonies and technical design discussions.

Skills

Java

Spring Boot

.NET Core

REST APIs

SQL

Docker

Kubernetes

OpenShift

CI/CD

Automated testing

Agile practices

Tools

Docker

Kubernetes

OpenShift

Job description

Backend Developer (Java or.NET)

Location: Warsaw (Hybrid - 3days per week in the office)
Start Date: ASAP / Flexible
Cooperation Model: B2B via Experis

We are looking for an experienced Backend Developer to join an international team building and maintaining scalable backend services and APIs powering client-facing portal applications.

Responsibilities

• Develop and maintain backend services and REST APIs using Java (Spring Boot) or .NET Core.
• Design and integrate solutions with relational and NoSQL databases.
• Collaborate closely with frontend teams to deliver seamless integrations.
• Build and deploy applications in containerized environments using Docker, Kubernetes, or OpenShift.
• Implement secure coding practices, automated testing, and CI/CD pipelines.
• Optimize application performance, scalability, and reliability.
• Troubleshoot production issues and support application stability.
• Participate in Agile ceremonies and technical design discussions.

Requirements

• 8+ years of backend development experience.
• Strong expertise in Java or .NET.
• Hands‑on experience building and consuming REST APIs.
• Experience with Docker, Kubernetes, or OpenShift.
• Solid SQL and database knowledge.
• Experience with CI/CD pipelines and automated testing.
• Strong communication and teamwork skills.

Nice to Have

• Experience with Kafka, MQ, or other messaging technologies.
• Cloud‑native development experience.
• Background in financial services, fund administration, or transfer agency environments.

What We Offer

• B2B contract via Experis
• Long‑term international projects
• Medicover healthcare package
• Multisport card
• Group life insurance