Software Engineer (Kotlin&Java)

thecodest; Warszawa; On-site; PLN 167,000 - 223,000; Full time

Benefits offered by this job

Worksmile platform

Growth opportunities

Competitive PLN salary

Job summary

The Codest in Warsaw is seeking a Senior Backend Engineer to design, develop, and maintain scalable services using Kotlin, Java and Spring Boot. You will work on a microservices architecture and collaborate with cross-functional teams to deliver high-quality APIs.

You’ll leverage MongoDB, GCP, and AI-assisted coding tools to accelerate delivery while upholding best practices. The role offers growth, a B2B contract, and a vibrant, international team.

Qualifications

• Proficiency in Kotlin and Java backend development.
• Experience with microservices design and deployment.
• Strong API design and testing.
• Ability to work with cross-functional teams.
• Familiarity with cloud platforms (GCP) and MongoDB.
• Experience with AI-assisted development tools.
• Commitment to engineering best practices.
• Proven track record of writing high-quality, maintainable code.

Responsibilities

• Design, develop, and maintain scalable backend services and APIs.
• Build microservices-based solutions focusing on reliability and performance.
• Architect new modules and guide key technical decisions.
• Optimize existing systems for scalability and code quality.
• Collaborate with Product, Data Analysts, and UX Designers.
• Work with MongoDB, Spring Data MongoDB, and GCP.
• Write tests and ensure high-quality, well-tested code.
• Contribute to frontend or mobile tasks when needed.
• Follow engineering best practices and CI/CD processes.

Skills

Kotlin

Java

Spring Boot

Microservices

Backend APIs

AI Tools

GCP

MongoDB

Team Collaboration

Code Quality

Tools

MongoDB

Spring Data MongoDB

Google Cloud Platform (GCP)

Job description

Hello World!

We are The Codest - International Tech Software Company with tech hubs in Poland delivering global IT solutions and projects. Our core values lie in “Customers and People First” approach that prioritises the needs of our customers and a collaborative environment for our employees, enabling us to deliver exceptional products and services.

Our expertise centers on web development, cloud engineering, DevOps and quality. After many years of developing our own product - Yieldbird, which was honored as a laureate of the prestigious Top25 Deloitte awards, we arrived at our mission: to help tech companies build impactful product and scale their IT teams through boosting IT delivery performance. Through our extensive experience with product development challenges, we have become experts in building digital products and scaling IT teams.

But our journey does not end here - we want to continue our growth. If you’re goal-driven and looking for new opportunities, join our team! What awaits you is an enriching and collaborative environment that fosters your growth at every step.

Project description:

Our client is one of the largest e-commerce platforms in Europe, used by millions of users every day. The company connects sellers - from small businesses to global brands - with customers, offering a vast product selection, fast delivery, and a well-crafted shopping experience.

Designing a vertical-specific user experience for the automotive category as part of company’s key strategic initiative, aimed at transforming the platform from a general-purpose marketplace into a collection of specialized “stores within a store.”

The role:

• Design, develop, and maintain scalable backend services and APIs using Kotlin, Java, and Spring Boot.
• Build and evolve solutions based on microservices architecture, ensuring their reliability, performance, and maintainability.
• Design the architecture of new modules and backend components and contribute to key technical decisions.
• Continuously optimize and improve existing systems, identifying opportunities to enhance performance, scalability, and code quality.
• Work with MongoDB, Spring Data MongoDB, and Google Cloud Platform (GCP) as part of the application ecosystem.
• Write and maintain high-quality, well-tested code while following established engineering best practices.
• Use AI-assisted and agentic coding tools as part of the daily software development workflow.
• Collaborate closely with Product Managers, Data Analysts, UX Designers, and other engineers to translate product and business needs into effective technical solutions.
• Occasionally contribute to areas beyond the backend, including web or mobile development, depending on project needs.

• Ability to effectively use AI-assisted development tools, such as GitHub Copilot, OpenCode, or other agentic coding tools, as part of your daily development workflow.

• Strong proficiency in both Kotlin and Java.
• Hands‑on experience in developing backend applications using Spring Boot.
• Experience in designing and implementing solutions based on microservices architecture.
• Strong focus on building, testing, and maintaining high-quality backend services and APIs.
• Ability to design the architecture of new modules and proactively identify opportunities to optimize and improve existing systems.
• Experience working closely with product and business teams, including Product Managers, Data Analysts, and UX Designers, to define and refine technical and functional requirements.
• Strong understanding of software engineering best practices and commitment to maintaining high engineering standards.

Nice to have:

• Versatility and cross-functional skills – hands‑on knowledge of frontend or mobile technologies (Web / iOS / Android) at a level that allows you to take on tasks beyond the backend domain.
• Intermediate knowledge of MongoDB and Spring Data MongoDB.
• Hands‑on experience working with cloud platforms, with a particular focus on Google Cloud Platform (GCP).

Our offer:

• 15-20k PLN on a B2B contract
• Access to the Worksmile platform
• A work environment that values growth and innovation - you bring the ideas, and we want to hear them