Senior Software Engineer

Senior Software Engineer at kraken.com.

About the role Become a core contributor to the Payward Services division, the engineering group responsible for the enterprise-grade infrastructure that drives global digital asset trading and payment operations. This position centers on crafting high-throughput, resilient backend systems that empower financial institutions to embed sophisticated cryptocurrency and liquidity workflows. You will operate at the intersection of traditional finance and blockchain technology, solving intricate architectural challenges that demand both precision and scale. The role offers the autonomy to shape technical direction within a massive engineering organization dedicated to redefining how value moves across borders.

Key facts

• Location: United Kingdom (Remote)
• Engagement: FullTime
• Team: Payward Services

What you’ll do

• Architect and implement core services and reusable libraries using Rust, targeting the stringent demands of trading engines and payment settlement flows.
• Write idiomatic, thoroughly tested, and performant code that upholds rigorous security postures and latency benchmarks.
• Design and evolve distributed architectures capable of meeting sub-millisecond latency requirements while accommodating elaborate product specifications.
• Collaborate across a vast engineering ecosystem to elevate technical standards, refine development lifecycles, and accelerate product delivery velocity.
• Take end-to-end ownership of complex initiatives, steering them from initial architectural blueprints through production deployment and ongoing observability.
• Diagnose and resolve intricate issues spanning the full technology stack, including operating system internals, network topology, and runtime behavior.
• Mentor junior engineers through code reviews, pair programming, and architectural guidance, fostering a culture of technical excellence.
• Evaluate and integrate emerging technologies or patterns that enhance system reliability, developer productivity, or operational simplicity.
• Participate in on-call rotations and incident response procedures to ensure the continuous availability of mission-critical financial infrastructure.
• Contribute to the definition of service-level objectives (SLOs) and service-level agreements (SLAs) for enterprise-facing APIs.
• Optimize data serialization, transport protocols, and concurrency models to maximize throughput on commodity hardware.
• Engage directly with product managers and stakeholders to translate ambiguous business requirements into concrete technical specifications.

Requirements

• A minimum of five years of professional software engineering experience building production-grade systems.
• Expert-level command of Rust, with deep practical experience in asynchronous runtimes (such as Tokio), network programming, and zero-cost abstractions.
• Proven track record designing systems where security, fault tolerance, and data integrity are primary architectural constraints.
• Demonstrated ability to independently debug complex failures across the stack, from kernel-level interactions and TCP/IP nuances to application logic.
• Extensive hands-on experience with distributed system patterns, specifically Event-Driven Architectures, Apache Kafka ecosystems, and Remote Procedure Call (RPC) frameworks (e.g., gRPC, Cap'n Proto).
• History of successfully leading projects through the full software development lifecycle: requirements gathering, design docs, implementation, testing, release, and maintenance.
• Strong communication skills enabling effective mentorship of peers and the ability to influence engineering culture and best practices across teams.
• Solid understanding of database internals, consensus algorithms, or state machine replication as applied to high-availability systems.

Nice to have

• Prior experience delivering B2B software products within the fintech, payments, or cryptocurrency domains.
• Familiarity with blockchain node operation, consensus mechanisms, or smart contract execution environments.
• Experience with formal verification methods, property-based testing, or chaos engineering practices.
• Background in optimizing Linux kernel parameters, network stack tuning (e.g., XDP, eBPF), or hardware acceleration (FPGA/GPU).
• Contributions to open-source Rust crates or core infrastructure projects widely used in the industry.
• Knowledge of regulatory compliance frameworks relevant to digital asset custody or transmission (e.g., Travel Rule, MiCA).

Skills & tools

• Rust (Async, Tokio, Tower, Serde)
• Distributed Systems Architecture
• Apache Kafka / Event Streaming Platforms
• RPC Protocols (gRPC, Protobuf, Cap'n Proto)
• Event-Driven & Message-Driven Systems
• Linux Internals & Network Stack
• Observability Stack (Prometheus, Grafana, OpenTelemetry, Jaeger)
• CI/CD & GitOps (GitLab CI, ArgoCD, Kubernetes)
• Database Systems (PostgreSQL, RocksDB, Redis)
• Cryptography Primitives (Ed25519, secp256k1, TLS/mTLS)

Practical notes Applications are reviewed on a continuous basis with no fixed closing date. Candidates are encouraged to redact sensitive personal identifiers such as age, date of birth, or graduation years from submitted resumes. The evaluation pipeline may incorporate practical coding assessments, system design discussions, and work-style questionnaires relevant to the role.

Payward Inc. operates as an equal opportunity employer; all qualified applicants receive consideration without regard to protected characteristics.

The position is fully remote within the United Kingdom; visa sponsorship details are not specified in the listing.

Salary bands are not publicly disclosed but are expected to be competitive for Senior Rust Engineers in the UK fintech market.