Remote Backend Engineer — Fintech APIs & Systems (Poland)

BJAK; Warszawa; On-site; PLN 180,000 - 260,000; Full time

Job summary

BJAK is seeking experienced backend engineers to build the core systems behind its AI Neobank app. You will craft reliable APIs and workflows that scale across markets, partners and millions of users.

The role emphasizes security, reliability and rapid feature delivery while collaborating with product, frontend, mobile and AI teams. Based in Poland, you will work remotely and contribute to onboarding, payments, KYC, risk and other financial product infrastructure that powers modern digital

Qualifications

• Strong backend engineering experience in production systems.
• Solid understanding of APIs, databases, authentication, and authorization.

Responsibilities

• Build backend services and APIs for onboarding, accounts, payments, cards, transfers, rewards, travel, FX, KYC and risk flows.
• Design reliable systems that can support real customer transactions and workflows.
• Integrate with internal systems, financial partners, payment providers, AI services and third-party platforms.
• Own backend quality across reliability, security, latency, observability, data integrity and incident handling.
• Collaborate with product, frontend, mobile and AI teams to launch features quickly and safely.
• Improve existing systems by simplifying flows and automating repeatable processes.

Skills

Backend engineering

APIs

Databases

Authentication

Authorization

Queues

Events

Security

Reliability

Data quality

Education

Bachelor's degree in CS/Engineering

Job description

BJAK is seeking experienced backend engineers to build the core systems behind its AI Neobank app. You will craft reliable APIs and workflows that scale across markets, partners and millions of users.

The role emphasizes security, reliability and rapid feature delivery while collaborating with product, frontend, mobile and AI teams. Based in Poland, you will work remotely and contribute to onboarding, payments, KYC, risk and other financial product infrastructure that powers modern digital