Join us in revolutionizing banking with the world's first autonomous financial core built for Tier-1 scale, replacing legacy monolithic cores with a modern, AI-enabled platform that reimagines how the world's largest banks operate.
Our mission is to bring elegance, composability, and truly open architectures to a massive, highly regulated industry. If you're passionate about complex distributed systems and mission-critical code, come help shape the future of core banking in an AI-native world.
While our engineering hub is based in London, we have a growing presence in Budapest and are now hiring for this role in both locations.
About OpenCoreOS
A "Thin Ledger," not a thick core: We provide a hyper-performant ledger using Go, Rust, and multi-region distributed databases. This gives banks a simple, powerful, and open foundation to build on, not a monolithic cage
AI-native by design: AI isn't an add-on; it's woven into our fabric. We use it to power autonomous operations, create agentic development workflows, and build an intelligent, self-healing system
Unbreakable and open: We engineer for five-nines reliability and bulletproof consistency, targeting the scale of a Tier-1 bank managing hundreds of millions of transactions daily. By building on open technologies and shaping new standards, we ensure our platform provides a foundation for innovation, not another form of lock-in
Backed by proven industry builders: Our leadership team combines the strategic insight of ex-McKinsey banking, product, and engineering experts with the battle-tested experience of a founder who built and scaled a mission-critical enterprise fintech company serving the world's largest banks. This is paired with the firsthand operational knowledge of former global bank CIOs, giving us an unparalleled understanding of the market we are redefining
What You Will Do
Core Financial Systems: Build mission-critical services that record and move value with strong correctness guarantees.
Transaction Processing: Implement safe, reliable transaction flows that behave predictably under retries and partial failures.
Performance: Profile and optimize hot paths to keep p95/p99 latency predictable and throughput scalable.
Reliability & Observability: Improve metrics, tracing, logging, alerting, and incident readiness for production systems.
AI-Native Dev Experience: Use and improve AI-assisted workflows for debugging, operations, and developer productivity.
Core Responsibilities
Build and operate production systems end-to-end (design → ship → run).
Enforce invariants and safety via testing, reviews, and disciplined change management.
Debug distributed/system-level issues (concurrency, performance, data consistency).
Drive operational excellence (SLOs, on-call, postmortems, automation).
Collaborate cross-functionally to turn requirements into simple, safe primitives/APIs.
Essential Skills
Strong systems engineering experience in Go and/or Rust.
Distributed systems fundamentals (consistency, fault tolerance, failure modes).
Performance and concurrency expertise (profiling, tail latency, debugging).
Operational maturity (observability, incident response, production ownership).
Security-minded and quality-focused (auditability/traceability where required).
Nice-to-Haves
Fintech/core banking/payments experience (or other high-correctness domains).
Regulated production experience (controls, audits, change discipline).
Low-latency/high-throughput background.
Strong observability practice (tracing/logging standards, production tooling).
Deterministic Simulation Testing
Benefits Overview:
4 Weeks of PTO
Medical & Dental Insurance
Eligible for Sign on Bonus
Pension
Paid National Holidays
Annual Bonus Eligibility
Why join us?
Massive impact: Transform how T1 banks handle billions of transactions daily—on a truly open platform.
High-caliber team: Join a small team of exceptional engineers who value both speed and stability.
AI-native workspace: Experience an AI-first environment with LLMs integrated into every tool.