Senior Software Engineer (Backend) (Crypto Payments)

Location: Bulgaria, South Africa, Poland, or Spain; hybrid/remote working policy

Salary: €70,000–€110,000 EUR in Bulgaria; €85,000–€110,000 EUR in Spain; PLN 250,000–480,000 in Poland

Company

hirify.global provides stablecoin and fiat payment infrastructure for enterprises, enabling money movement, conversion, settlement, and financial product development across global markets; it is part of Mastercard.

What you will do

• Design, build, and operate high-throughput backend services orchestrating crypto pay-ins, pay-outs, conversions, and transfers across assets and blockchain networks.
• Build and evolve versioned, documented public and internal APIs for merchants and partners.
• Improve payment correctness and reliability using idempotency, transactional outbox, retries, and dead-letter handling.
• Optimize performance and scalability across hot paths, databases, and service-to-service communication.
• Modernize legacy services into modular, domain-aligned boundaries and build asynchronous, event-driven workflows.
• Own production operations, including monitoring, alerting, on-call participation, incident response, root cause analysis, collaboration, and engineer mentorship.

Requirements

• Solid professional experience building and operating production backend systems at scale.
• Strong proficiency in Java, ideally Java 17+, and Spring Boot.
• Hands-on experience with microservices and event-driven architectures using brokers such as Kafka or SQS, including transactional outbox, idempotency, and eventual consistency.
• Strong experience with MySQL or PostgreSQL, including schema design, indexing, query tuning, and safe migrations.
• Experience with AWS, Docker, Kubernetes, CI/CD pipelines, and observability for metrics, tracing, and logging.
• Experience building payment, banking, or other financial systems where correctness, auditability, and reliability matter.
• Strong testing mindset across unit, integration, and contract tests, with a focus on clean, maintainable code.
• Early adoption of AI coding tools and agentic workflows for designing, building, and testing solutions.
• Ownership from idea to production, clear communication with technical and non-technical colleagues, and openness to an out-of-hours on-call rota.

Nice to have

• Kotlin, caching with Redis, stablecoins, blockchain networks, crypto wallets, or crypto payment processing experience.
• Domain-driven design, modular architecture, or large-scale legacy-service refactoring experience.
• Experience with Temporal, workflow engines, rule engines, or scheduling systems.

Culture & Benefits

• Flexible working hours with hybrid working at the core.
• Flexible holiday policy and opportunities to travel to offices around the world.
• Open, creative, growth-minded environment focused on shaping the future of hirify.global.
• Competitive compensation based on experience and relevant certifications.
• Diverse and inclusive workplace.