Staff Backend Engineer

Department: Engineering

Location: Poland

Employment Type: FullTime

Our mission is to enable everyone to build wealth

We reinvent how trading and investing work by creating exceptional products people love.

That takes high standards, high velocity and engineers who own what they ship.

Today, we serve over 6 million clients, with more than €38 billion in assets under management. At that scale, performance, reliability and data integrity are part of the product.

Our platform is powered by a modern, high-performance engineering stack designed for scale and reliability: Java 21 (Spring), Go, Node.js (TypeScript), PostgreSQL, MariaDB, Redis, Kafka, ClickHouse, Elasticsearch, Docker, Grafana, AWS, Kubernetes and Kibana.

About the role

Staff Backend Engineers shape technical direction across teams while remaining close to the systems and code. You will take on problems whose consequences extend beyond one service or delivery cycle.

This is not a people-management role. Its leverage comes from technical judgement, credible execution and the ability to help other engineers make better decisions.

What you’ll do

• Own high-consequence backend problems that span services, teams or product domains.

• Establish clear system boundaries and architectural direction without creating unnecessary central control.

• Lead technical decisions by making constraints, alternatives, risks and trade-offs explicit.

• Improve performance, resilience, data integrity, operability and failure handling across production systems.

• Resolve recurring structural problems rather than treating symptoms team by team.

• Remain hands-on where implementation, diagnosis or prototyping is the fastest way to create clarity.

• Mentor senior engineers, raise review quality and make strong engineering judgement easier to reproduce across teams.

• Partner with engineering and product leaders on sequencing, risk and long-term technical investment.

What you need to have

• Evidence of technical impact across multiple teams or a substantial product domain.

• Deep ownership of distributed backend systems operating at meaningful scale.

• Strong judgement in service boundaries, asynchronous communication, data ownership, consistency and failure modes.

• Deep knowledge of relational databases, transactions, concurrency and high-performance design.

• A track record of improving reliability, scalability, observability or developer effectiveness through durable mechanisms.

• The ability to influence technical direction through evidence, clarity and trusted execution rather than title.

• Clear communication that helps teams act on complex technical decisions.

• Strong engineering fundamentals and the judgement to choose when to standardise, simplify or leave a system alone.

Staff scope is assessed through ownership, judgement and sustained organisational impact—not years of experience or familiarity with every technology listed.

What to expect

• Recruiter conversation

• Code Review

• System Design

• Managerial interview

Your recruiter will explain each stage clearly and follow up after every conversation.

Bring your ambition to Europe’s fastest-growing mobile broker!