Senior JVM Engineer: Kotlin/Java, AI & Large-Scale Backend

Allegro.eu S.A.; Poland; Hybrid; PLN 163,000 - 232,000; Full time

Benefits offered by this job

Hybrid work model

English classes

Training budget

Volunteer day

Social events

Job summary

Allegro.eu S.A. Warsaw-based team in Technology is hiring for a backend engineer focused on massive-scale systems and applied AI.

You will design, build, and optimize services handling ~120 million offer events daily, integrating ML models to analyze images and offer context, while maintaining high-quality code and scalable architecture. You’ll work primarily in Kotlin, with opportunities to engage frontend tasks and open-source AI tooling.

Qualifications

• Commercial experience coding in Kotlin or Java (with eagerness to master Kotlin for new services)
• Value high-quality code and engineering best practices to solve complex challenges in massive-scale distributed systems
• Excited to implement and optimize AI models in a production environment
• Embrace a growth mindset, value team stability, and occasionally pick up frontend tasks (React is a nice-to-have)
• Communicate effectively in English (at least a B2 level)

Responsibilities

• Design, build, and optimize systems handling ~120 million offer events daily
• Integrate ML models and AI agents to analyze images and read offer context
• Automate offer and product verification to prevent policy breaches
• Work primarily in Kotlin backend with potential frontend involvement
• Contribute to AI infrastructure and open-weight model evaluation at scale

Skills

Kotlin/Java

AI/ML in production

Frontend familiarity

English (B2)

High-quality code

Tools

Kubernetes

Docker

Consul

GitHub

GitHub Actions

Job description

Allegro.eu S.A. Warsaw-based team in Technology is hiring for a backend engineer focused on massive-scale systems and applied AI.

You will design, build, and optimize services handling ~120 million offer events daily, integrating ML models to analyze images and offer context, while maintaining high-quality code and scalable architecture. You’ll work primarily in Kotlin, with opportunities to engage frontend tasks and open-source AI tooling.