Junior Backend Engineer

Synerise SA; Kraków; On-site; PLN 90,000 - 130,000; Full time

Job summary

Synerise SA is hiring a Junior Backend Engineer to join a production-grade, large-scale system used by enterprise customers worldwide. You will work on architecture, design patterns, and performance optimisations for high-volume data processing.

The role emphasizes translating complex requirements into robust backend solutions, with a strong focus on learning JVM languages, web frameworks, and distributed systems.

Qualifications

• Experience with JVM languages and backend development.
• Basic experience with at least one web framework.
• Familiarity with SQL or NoSQL databases.
• Experience using AI coding tools is a plus.

Responsibilities

• Develop architecture and design patterns to process and store high volume data sets.
• Develop software with a core focus around optimisation and performance.
• Translate complex functional and technical requirements into detailed design.
• Perform analysis of vast data stores and uncover insights.

Skills

Java

Scala

Kotlin

Rust

Web frameworks

SQL

NoSQL

AI coding tools

Tools

Claude Code

Cursor

GitHub Copilot

Job description

Synerise is not just another tech company. It is a space where our brilliant team consequently brings technology change to the business world and instead of following known paths, we are creating a new one – a next-generation, fully personalized, and AI-driven customer experience.

We successfully deliver an all-in-one tool – Synerise. An ever-evolving behavioral data platform, enhanced by AI to generate outstanding ROI in more than 30 markets for industry leaders in Retail, Banking, eCommerce, Automotive, Insurance, and Telco, processing more than 150 billion transactions annually. However, we don’t limit ourselves solely to this solution. We’re building BaseModel – a foundation model for behavioral data embedded within a novel platform for enterprise Data Science teams, that is another step on our path to create innovation in AI and demonstrate its potential for the business world.

Having such great solutions, we are looking for a highly motivated Junior Backend Engineer to join our brave and brilliant Synerise Team. See if you fit our diverse and dynamic environment, where we constantly evolve together with the growth of our clients.

About the team

Our Backend Team works primarily with Scala, Apache Kafka, ElasticSearch, Clickhouse, Kubernetes, and cloud environments (Azure and GCP). Observability is a first-class concern: distributed tracing (OpenTelemetry, Jaeger), structured logging, and rich metrics are embedded into how we design and operate services.

What will you do on a daily basis?

• Develop architecture and design patterns to process and store high volume data sets.

• Develop software with a core focus around optimisation and performance.

• Translate complex functional and technical requirements into detailed design.

• Perform analysis of vast data stores and uncover insights.

What will make us a perfect match?

• Programming skills in any JVM language (like Java, Scala,Kotlin) or Rust, and a strong willingness to learn them quickly.

• Basic experience with at least one web framework and an understanding of how web applications work.

• Familiarity with SQL or NoSQL databases and basic database queries.

• Hands-on experience using AI coding (e.g., Claude Code, Cursor, GitHub Copilot) as part of daily software engineering work.

• Decent troubleshooting and analytical skills with a methodical approach to solving technical problems.

• A passion for building tools and learning new technologies.

• Strong analytical and communication skills.

What will convince us even more?

• Existing GitHub/Gitlab portfolio or personal projects.

• Experience with microservices architecture.

• Basic knowledge of AI/ML concepts.

What can we provide for you?

• Work on a production-grade, large-scale system used by enterprise customers worldwide.

• Real technical challenges around performance, data volume, and distributed systems.

• Opportunities for continuous technical growth and deeper ownership over system design.

• Support from experienced engineers and a strong engineering culture.

• Influence on architectural and technical decisions within your team.