Senior Software Engineer

Senior Software Engineer

London / Madrid / Malaga

Perm Role | Hybrid (4 Days Onsite)

Competitive Salary + Discretionary Bonus

Harrington Starr has partnered with a leading global fintech organization to hire a Senior Software Engineer for its high‑performing engineering team. This role offers the opportunity to design, build, and scale critical payment infrastructure supporting high‑volume, multi‑currency transactions across international markets. Working within a collaborative and globally distributed environment, you will play a key role in shaping the next generation of the firm’s core payments platform.

• Design, build, and scale mission‑critical payment and fund‑collection services.
• Own solutions end‑to‑end, from architecture and development through to production support.
• Partner with Product and Operations teams to translate business requirements into technical solutions.
• Mentor engineers and contribute to engineering best practices and code quality.

• Strong experience building and operating scalable, highly available backend systems.
• Background in payments, fintech, banking, or other transaction‑heavy environments.
• Experience with distributed systems, APIs, asynchronous messaging, and relational databases.
• Passion for clean code, testing, observability, and continuous improvement.
• Excellent communication skills and ability to collaborate with technical and non‑technical stakeholders.

• Backend development using Python, Django, and FastAPI.
• Building scalable solutions with PostgreSQL and Kafka.
• Deploying and operating cloud‑native applications on AWS and Kubernetes.
• Infrastructure automation and CI/CD using Terraform and Jenkins.
• Monitoring, observability, and platform health management with Prometheus and Kibana.

• Competitive salary and performance‑related bonus.
• Opportunity to work on large‑scale, business‑critical systems.
• International, collaborative engineering culture.
• Ongoing professional development, training, and certification support.

If you are interested in finding out more information or would like to book a confidential call, please apply!