Mid or Senior Software Engineer

Payments infrastructure is broken for subscription businesses - and most people don’t even

know it until chargebacks start piling up.

polar night is chargeback defense and intelligence built for companies running complex

payment stacks: orchestration layers, multiple PSPs, multi-brand operations, high transaction volume. We connect what payment stacks fragment and give the full picture: unified dispute data, real-time alert matching, AI-native anomaly detection, and the tools to act on it.

We’re a small, senior team that built this because we came from the merchant's world. We know what’s broken because we lived it.

The Role

We’re looking for a Mid or Senior Software Engineer to join our core engineering team.

You’ll be working on a backend-heavy system - building the APIs, integrations, and data pipelines that power our platform.

This is an early-stage role with real ownership. You won’t be handed a ticket queue. You’ll be shaping how things get built, you’ll have a real impact.

What You’ll Work On

• Payment integrations - building and maintaining connections to orchestration platforms and payment providers

• Data ingestion & enrichment - pipelines that ingest data and enrich it across sources, with no gaps

• Analytics & reporting - backend APIs that power chargeback analytics and custom merchant views

• AI-native features - contributing to anomaly detection, smart recommendations, and natural language query capabilities built on top of our data

Must-have

• 4+ years of backend experience with TypeScript / Node.js

• Comfort building and maintaining APIs and third-party integrations

• Experience with complex data models, event-driven architecture, or real-time data processing

• Strong debugging and problem-solving instincts - you find the root cause, not just the symptom

• Ability to own work end-to-end: design, build, ship, monitor

Great to have

• Experience in payments or subscription billing (or genuine curiosity about how it works)

• Familiarity with PSP APIs (Stripe, Adyen, or similar)

• Experience with cloud infrastructure (GCP or AWS)

• Some front-end experience - enough to read, contribute to, and understand internal dashboard system.

How We Work

• We’re a small team that moves fast and trusts each other to make good decisions.

• No micromanagement - you own your work

• Data-driven: we measure what matters, and we’re honest about what the numbers say

• Direct feedback, no politics

• We’re building in a genuinely complex domain - the technical problems here are real, not artificial, so is the business case.

What We Offer

• €5,000 - €7,000 gross/month, depending on experience.

• Fully remote - based in Lithuania.

• Flexible working hours - we care about output, not hours logged.