Mid Backend Software Engineer

Implement new micro-services and extend existing ones in Go.

Help groom user-story requirements and surface performance / scaling concerns early.

Write unit, integration and API tests; review PRs.

Tune data-models in DynamoDB & Postgres for low-latency, high-throughput workloads.

Pair with DevOps on CI/CD and observability improvements.

Participate in on-call rotation as we’re building high available fintech system

Additional tasks of the Senior

Design and drive high-scale, low-latency services (tens of thousands of orders / sec).
Lead architecture reviews, challenge assumptions and keep tech debt in check.
Partner with Product on roadmap feasibility & effort sizing.
Be a mentor to less experienced colleagues

3+ years of professional back-end experience (ideally 1 year+ in Go).

Solid grasp of cloud-native design (RESTful APIs, event-driven patterns).

Working SQL and NoSQL skills; know when each shines.

Comfort diagnosing performance bottlenecks in distributed systems.

Ability to work on-site in Warsaw twice a week (Tue & Thu) and remotely otherwise.

Exposure to serverless architectures on AWS.

Experience with Kafka or another high-volume message bus.

Knowledge of automated trading, market data, or FIX/crypto exchanges.

Familiarity with Infrastructure-as-Code (Terraform or CDK).

B2B / Employment contract

Hybrid (Warsaw – in-office every Tuesday & Thursday)

What We Offer:

An experienced, welcoming team that loves clean, well-tested code.

Real impact: the features you ship go straight into production for live traders.

Flexible hours, modern tooling, and a fintech domain that’s never boring.

Occasional work travel to Germany (Munich / Berlin)

20 days PTO on B2B

Multisport card

Senior or Mid Backend Software Engineer (m/f/d)