Job Title: Senior Java Developer (API & Legacy Modernisation)

Location:

Remote – Spain

Rate:

€400 per day

Contract:

6-month rolling contract

About the Role

We’re looking for an experienced

Senior Java Developer

to join a financial services programme focused on modernising legacy platforms and building high-quality APIs. This is a long-term contract opportunity for someone who thrives in complex enterprise environments and enjoys transforming legacy systems into scalable, modern architectures.

Key Responsibilities

Design and develop robust, secure, and scalable

Java-based APIs and microservices

Lead and contribute to

legacy system modernisation

initiatives

Work closely with architects, product owners, and DevOps teams to deliver high-quality solutions

Improve system performance, reliability, and maintainability

Contribute to technical design, code reviews, and engineering best practices

Support integration with internal and external financial systems

Ensure solutions meet security, compliance, and regulatory standards

Required Experience & Skills





10+ years of Java development experience

Strong experience in

API development

(RESTful services, microservices architecture) Proven track record in

legacy platform modernisation

and refactoring

Solid knowledge of:

Spring / Spring Boot ecosystem

Microservices and distributed systems

Cloud platforms (AWS, Azure, or GCP) CI/CD and DevOps practices

SQL and NoSQL databases

Experience working in

financial services / banking / fintech

environments

Strong understanding of security, scalability, and high-availability systems

Excellent communication skills and ability to work in distributed teams

Nice to Have

Experience with containerisation (Docker, Kubernetes) Event-driven architectures (Kafka or similar) Experience with domain-driven design (DDD)

Why Join? Competitive €400/day

rate

Fully remote role within Poland

Long-term 6-month rolling contract

Opportunity to work on high-impact modernisation projects in financial services

📌 Senior Java Software Engineer - €400 A Day - Remote (Soñar)
🏢 Oliver Bernard
📍 Soñar