Kotlin/Java Engineer w Warszawa, Polska

Our Mission and Vision

At Solidgate, our mission is clear: to empower outstanding entrepreneurs to build exceptional internet companies. We exist to fuel the builders — the ones shaping the digital economy — with the financial infrastructure they deserve. To achieve that, we're on a bold path: to become the #1 payments orchestration platform in the world.

We believe the future of payments is shaped by people who think big, take ownership, and bring curiosity and drive to everything they do. That's exactly the kind of teammates we want on board.

Solidgate is part of Endeavor — a global community of the world's most impactful entrepreneurs. We're proud to be the first payment orchestrator from Europe to join — and to share our expertise within a network of outstanding global companies.

About the Team and Role

You'll join the Core team — the team responsible for the services that sit at the heart of Solidgate's payment processing. Core services define what a payment is, integrate with numerous internal services for correct routing, run antifraud checks, and process payments through providers, covering card payments as well as Apple Pay and Google Pay. This is the critical path for every payment on the platform, so the team's work directly defines the reliability and speed of the whole system.

The team is actively growing new functionality, supporting existing services, working down technical debt, and maintaining an SLO of 99.99%+ across all of its services. The stack is built around high-load, low-latency requirements: a microservices architecture with Kotlin as the primary language, Protobuf RPC over Buf/Connect, PostgreSQL as the main database, and Kafka for asynchronous processing, with fully automated production deployments and an advanced monitoring and observability setup. Infrastructure is continuously improved by a dedicated platform team, with IaC ensuring transparent, reproducible, and scalable management.

Your team — Product Manager, Tech Lead (Backend), three Backend Software Engineers (Senior), one Frontend Software Engineer (Middle), AQA Engineer, and System Analyst.

Explore our technology stack ➡️ here .

What you'll own

Your focus will be on:

• taking part in product decisions across the full development lifecycle
• designing and developing backend functionality for our products
• collaborating with other teams to build reliable solutions for payment processing
• improving the performance, scalability, quality, and reliability of our systems

You'll grow from feature-level tasks toward owning a dedicated service or domain, taking part in the team's design and technical decisions.

You're a great fit if you have

• 3+ years of experience with Java
• Confident hands-on experience with SQL databases (PostgreSQL/MySQL)
• Experience designing reliable, scalable systems
• Experience with distributed systems
• Experience with cloud environments (AWS/GCP)
• Technical/computer science-related degree
• 2+ years of active hands-on use of AI tools
• Upper-Intermediate English or fluent Ukrainian

Nice to have

• Experience with Kotlin
• Fintech experience and experience with high-load, complex systems
• Observability/Alerting tools (Prometheus, Grafana)
• Infrastructure as Code (Terraform)
• Message brokers (Kafka/SQS/RabbitMQ)

Why Solidgate?

High-impact role . You'll work at the very core of our payment processing — the critical path for every transaction, including Apple Pay, Google Pay, and card payments.

Great product. We've built a fintech powerhouse that scales fast. Solidgate isn't just an orchestration player — it's the financial infrastructure for modern Internet businesses. From subscriptions to chargeback management, fraud prevention, and indirect tax — we've got it covered. We hold financial licenses in key regions and are a direct Visa & Mastercard partner and sub-reseller (top 5 globally).

Massive growth opportunity. Solidgate is scaling rapidly — this role will be a career-defining move.

Top-tier tech team. Work alongside our driving force — a proven, results-driven engineering team that delivers.

Modern engineering culture.  TBDs, code reviews, solid testing practices, metrics, alerts, and fully automated CI/CD.

The Extras: 30+ days off, unlimited sick leave, free office meals, health coverage, and Apple gear to keep you productive. Courses, conferences, sports and wellness benefits — all designed for ideas, focus, and fun.

Tomorrow's fintech needs your mindset. Come build it with us.

Know top talent? We're always on the lookout.  Refer someone for our role, and if they get hired, there's a bonus waiting for you — simple as that.