Senior Java Engineer (Payments)

We’re looking for a Senior Java Engineer to join Payforge and take technical ownership of reliable, scalable payments platforms — the systems that move money securely, at scale, where getting it wrong isn’t an option. We’re looking for a Senior Java Engineer to join Payforge and take technical ownership of reliable, scalable payments platforms — the systems that move money securely, at scale, where getting it wrong isn’t an option. We’ve just begun working with a few of the most recognised names in global payments — organisations whose infrastructure sits behind everyday transactions — so the scale is real and the engineering bar is high. As a specialist payments consultancy, we offer variety: new clients, new platforms, and hard problems you haven’t solved before, rather than one codebase for the next five years. We’ve been fully remote from the start. Key Responsibilities Design, develop, and maintain enterprise-grade applications using Java and Spring Boot, owning features end-to-end from design through production. Lead technical design for significant components — defining service boundaries, data models, integration patterns, and non-functional requirements. Partner with product managers, solution architects, and DevOps engineers to translate business needs into technical solutions — and challenge requirements where the technical trade-offs matter. Own application reliability, performance, and compliance with security and regulatory standards. Build and maintain integrations with external systems, APIs, and third-party providers. Write clean, testable, efficient code and raise the bar for those around you. Drive improvements to CI/CD pipelines, automated testing, observability, and deployment processes. Lead code reviews, mentor mid-level and junior engineers, and act as a technical point of escalation. Own production incidents through root-cause analysis to durable fixes. Skills & Experience 7+ years of professional Java development experience, with a track record of owning non-trivial systems in production. Practical, day-to-day use of AI coding assistants and LLMs as part of the development workflow — for implementation, refactoring, test generation, debugging, and documentation — combined with the engineering judgement to review and validate what they produce for correctness, security, and maintainability. We use these tools heavily across everything we build, and we expect them to be directed by an engineer who knows when the output is wrong. Hands-on experience building or operating payments or fintech systems — card issuing, acquiring, processing, authorization, settlement, cross-border, or equivalent. You should be comfortable with the realities of money movement: idempotency, reconciliation, transaction lifecycles, and the regulatory constraints that come with them. Strong knowledge of Java 21/25 (LTS) and Spring Boot 4 / Spring Framework 7, building RESTful and event-driven microservices. Solid experience with Apache Kafka and asynchronous processing, including idempotency and exactly-once semantics. Experience with relational databases (PostgreSQL, MySQL) and ORM frameworks (Hibernate, JPA). Strong API design skills (REST, OpenAPI) and integration best practices. Confident with modern build tooling — Gradle and Maven — and with CI/CD pipelines (GitHub Actions, Helm, Terraform). Hands-on experience with AWS, Docker, and Kubernetes. Strong testing discipline (JUnit 5, Mockito, Testcontainers) and production observability (OpenTelemetry, Prometheus, Grafana). Experience mentoring engineers, leading code reviews, and working in distributed teams. Nice to have Depth in payments standards and protocols: ISO 20022, ISO 8583, EMV, 3-D Secure, or scheme certification. Depth in security: encryption, OAuth2/OIDC, JWT, mTLS, HSM integration, tokenization. Infrastructure-as-code and platform engineering experience. Experience working directly with enterprise clients in a consultancy or professional-services setting. What w