Mission freelance Java API Developer

The Role
We are seeking an experienced Java API Developer to join our Digital Asset development team. This is a hands on engineering role responsible for building and operating secure, resilient API services that power institutional digital asset capabilities-spanning digital custody, tokenization enablement, digital transfer agency, and digital cash/settlement workflows. You will work closely with cross-functional teams to build robust, scalable, and secure digital asset products that meet our business and technical requirements.

Your responsibilities:
* Design, develop, and maintain Java backend services and REST APIs that support digital asset product flows (custody, tokenization, TA, digital cash/settlement) and integrate cleanly into the broader platform.
* Build API services that participate in the platform's centralized integration approach-supporting client/app onboarding and app-to-service integrations via an Integration Hub and secure gateways.
* Implement APIs that align to enterprise API design/security/publishing requirements, ensuring designs are review-ready and compliant with internal standards (security, documentation, and platform requirements).
* Partner with product, architecture, and security stakeholders to implement policy-aware integration patterns
* Contribute to digital asset data patterns, including standardized interfaces and integration points such as Digital Data Interface and Digital Event Stream concepts where applicable for downstream reporting/analytics and operational workflows.
* Build and maintain automated tests (unit/integration) and ensure strong quality gates for services supporting regulated digital asset processing.
* Support production readiness: observability (logs/metrics), incident triage, performance tuning, and resilience improvements for APIs operating in a regulated, high availability environment.
* Collaborate across teams to drive clear API contracts and dependencies for integrations to traditional platforms (e.g., custody/cash/fund accounting) as part of a hybrid digital + traditional operating model.
Your Profile



Essential skills/knowledge/experience:
* Strong experience building Java backend APIs (REST) in financial services, ideally including digital assets or closely related domains (custody, cash, fund services, or regulated platforms).
* Hands on expertise with Spring Boot and common Spring components used for API services (web, security, data access).
* Hands-on experience deploying and operating containerized Java microservices on Kubernetes (e.g., AKS), including working knowledge of core concepts such as Deployments, Services, Secrets, resource requests/limits, and basic troubleshooting in clustered environments
* Experience working with relational databases (e.g., Oracle) and ORM/data access patterns
* Proven ability to design and implement API contracts with strong discipline around versioning, backward compatibility, and documentation, aligned to internal API Development Standards.
* Strong understanding of security-first API engineering in regulated environments (authentication/authorization patterns, secure integration paths, least privilege mindset).
* Experience delivering production-grade services with strong engineering practices (code reviews, automated testing, operational readiness).
* Experience working effectively with multi-location engineering teams.



Desirable skills/knowledge/experience:
* Experience building services that integrate with digital asset platform components such as tokenization, wallet management, smart contract management, or custody-related workflows.
* Familiarity with integration models that span traditional and digital, including standards-based messaging approaches and hybrid architectures used to connect platforms.
* Exposure to event/data distribution patterns for digital assets (e.g., event streams and data interfaces that feed reporting/analytics/monitoring).
* Understanding of digital asset ecosystem concepts (permissioned vs permissionless connectivity; third party DLT providers; secure key infrastructure/HSM adjacency at a platform level).
* Exposure to Node.js for front end support or lightweight backend-for-frontend (BFF) services, including working with REST APIs and understanding how Node.js services integrate with enterprise Java or platform backends.


LA International is an award-winning partner of choice for many of the world's most influential companies and government organisations. Holding Enhanced Government Security Accreditation, we are recognised as the European market leader in the delivery of Security Cleared talent to organisations that demand the very highest levels of security, compliance and assurance.

A multiple award-winning organisation, having secured the prestigious Queens Award for Enterprise: International Trade over consecutive years. We are committed to fostering an inclusive, equitable and accessible workplace where everyone feels valued and supported. We welcome applications from all individuals, regardless of background or identity, and we encourage candidates who may not meet every listed requirement to still apply. If you require any adjustments or support during the recruitment process, please let us know and we will work with you to ensure a fair and accessible experience.

Please Note: If a high volume of applications is received, only candidates shortlisted will be contacted.