Senior Full Stack Software Engineer - Payments Team

The Opportunity

We are seeking a seasoned Senior Full Stack Software Engineer to join our high-impact Payments Engineering team. In this role youll help drive the evolution of our payment platform supporting global payment flows including bank integrations policy premium collections refund processing and Stripe/PSP integrations. Youll work across the stack to build scalable APIs intuitive user interfaces and robust automation pipelines that power mission-critical financial transactions.

Were building modern cloud-native systems using .NET/C# Azure SQL and with a strong focus on automation-first development security and high availability. If you have experience in the payments domain including payment gateways reconciliation and transaction workflows this is an opportunity to make a direct impact on systems that process millions in revenue and support global policyholders.

Why Join Us

This is a pivotal role in a growing global organization that is transforming the life insurance experience. Youll contribute to a platform that manages payment lifecycle flows end-to-end from initial premium collection and recurring billing to refunds chargeback handling and bank API integrations (e.g. BACS ACH SEPA etc.).

Youll be empowered to shape system architecture influence DevOps practices and help standardize our integration with third-party payment providers like Stripe GoCardless and regional banks. Join an engineering culture that values automation scalability and inclusive collaboration.

Qualifications :

Key Responsibilities

Full-Stack Payments Engineering

• Design and develop scalable secure REST APIs in .NET/C# for payment-related services.
• Build responsive UIs using for managing payment flows (e.g. policy billing refunds).
• Develop integrations with external payment providers (e.g. Stripe GoCardless) and bank APIs (e.g. UK BACS AUS Westpac ACH etc.).
• Manage secure storage and transmission of payment data (PCI-DSS compliance awareness preferred).
• Handle edge cases including payment failure handling retries and reconciliation logic.

Automation and Quality

• Champion automation-first development: implement end-to-end testing using tools like SpecFlow Playwright and Gherkin.
• Contribute to test frameworks that ensure the accuracy of payment and refund logic.
• Lead code reviews and advocate for TDD/BDD practices across the team.

Platform Reliability and Observability

• Implement and maintain CI/CD pipelines for frequent safe releases.
• Develop observability tooling to monitor payment transaction health failures and latency.
• Participate in post-incident reviews and contribute to system hardening initiatives.

Domain Collaboration

• Work closely with Product Compliance and Finance to ensure secure and compliant handling of funds.
• Support premium lifecycle operations including initial billing renewals partial payments and cancellations.
• Help develop and maintain refund processing workflows including pro-rata calculations reversals and audit trails.

Required Qualifications

• 3 years in software engineering with strong full-stack experience.
• Proficient in .NET/C# JavaScript Azure SQL (MSSQL).
• Proven experience developing APIs and UI components in distributed systems.
• Experience working with payment systems (Stripe BACS ACH GoCardless etc.).
• Strong knowledge of test automation frameworks and CI/CD practices.
• Solid understanding of transaction integrity idempotency and financial system safety.

Preferred Qualifications

• Experience with Azure Cloud Kubernetes and containerized deployments.
• Familiarity with policy premium billing systems insurance domain or subscription management.
• Knowledge of financial reconciliation processes and ledger balancing.
• Background in security best practices related to handling sensitive payment data (e.g. tokenization PCI compliance).
• Strong communication and mentoring capabilities.

Additional Information :

We Offer

Neilson provides a competitive total compensation package extensive learning opportunities and a dynamic environment where you can grow your career. Compensation will be based on experience skill set and business needs. Additionally we we offer a robust benefits package including:

• 100% remote-first role with flexible working options
• Option of hybrid working (dependent on results and length of service)
• Pension healthcare life assurance
• Great central office only 2 minutes away from Windsor train station!
• Amazing bunch of people that genuinely want to support you and celebrate your wins!
• We work hard but we know how to have fun too; we have regular theme days and charity events for all to enjoy.
• Fancy a morning brew We have that covered! Tea coffee and milk provided!
• Employee Assistance Programme to help and support with life stuff!
• We have plenty of local discounts for coffee outlets restaurants cinemas and gyms and more
• Free fruit Flu Vaccinations Cycle to work scheme Eye Test/Glasses Vouchers looking after your wellbeing!
• 25 days holiday plus bank holidays

If youre a driven leader with a passion for engineering and team empowerment we want to hear from you. Join us at Neilson and help shape the future of our technology landscape.

Remote Work :

No

Employment Type :

Full-time