Aaron Lewis
Senior Backend & Platform Engineer
Financial & Regulated Systems
Senior backend-focused software engineer with extensive experience designing and delivering secure, cloud-native financial and eligibility platforms in highly regulated environments. Proven track record building event-driven, transactional microservices and decisioning systems that determine financial outcomes and handle sensitive data at scale. Experienced operating under strict compliance, audit, and availability requirements, with a strong interest in fintech, payments, and digital asset platforms.
Professional Experience
Software Development Consultant
- ▸Delivered backend platforms where correctness directly impacted financial eligibility, entitlement, and downstream payment outcomes, requiring high confidence in data integrity and decision logic.
- ▸Led development of event-driven, transactional microservices using Java, Kotlin, Spring Boot, and WebFlux, operating under strict governance and audit requirements.
- ▸Owned the design and delivery of secure API platforms integrating third-party services, enforcing authentication, authorisation, and encryption for financially sensitive data.
- ▸Architected and operated asynchronous pipelines using AWS SNS, SQS, EventBridge, Lambda, and Step Functions to ensure scalability, resilience, and traceability.
- ▸Established and maintained compliant cloud infrastructure using Terraform, embedding security, observability, and operational controls by default.
- ▸Acted as a senior technical presence within teams: mentoring engineers, leading refinement and architectural discussions, and maintaining delivery standards aligned to regulatory expectations.
Swarm Energy Limited
- ▹Developed cloud-native microservices performing daily cost and usage calculations, continuously ingesting high-volume device data to drive downstream automation and financial outcomes.
- ▹Implemented secure key management and encryption using AWS KMS, Auth0, and Spring Security to protect commercially sensitive credentials.
- ▹Built webhook-driven ingestion pipelines using API Gateway, EventBridge, and Lambda, ensuring reliable integration with third-party providers.
- ▹Designed infrastructure using Terraform to support scalable, fault-tolerant, business-critical production workloads.
Financial Eligibility & Decisioning Platforms (DWP)
- ▹Designed and delivered backend services underpinning financial eligibility, entitlement, and case-management workflows, replacing legacy systems with modern microservice architectures.
- ▹Built rules-driven decisioning APIs using Node.js and Java, subject to governance, audit, and regulatory approval.
- ▹Migrated critical workflows from monolithic systems to event-driven architectures, improving scalability, maintainability, and operational resilience.
- ▹Assumed technical leadership responsibilities during delivery-critical phases, including architectural ownership and cross-team coordination.
- ▹Work recognised via government award shortlisting, contributing to subsequent successful programme bids.
Full-Stack Software Engineer
- ▸Contributed to backend and frontend development for large-scale migration from legacy systems to modern microservice architectures.
- ▸Delivered new services adhering to TDD principles and modern agile delivery practices.
- ▸Participated in stakeholder demonstrations and technical walkthroughs, communicating complex system behaviour clearly to non-technical audiences.
Full-Stack Software Engineer Intern
- ▸Key contributor to the delivery of a flagship learning management platform, supporting weekly production releases.
- ▸Balanced rapid feature delivery with technical quality through code reviews, collaboration with QA, and close alignment with product design.
- ▸Conducted exploratory technical spikes to inform architectural decisions and continuous improvement.
Skills
Core Backend & Platform
JavaKotlinSpring BootWebFluxMicroservicesEvent-Driven Architecture
Cloud & Infrastructure
AWS LambdaSNS/SQSEventBridgeAPI GatewayTerraformDocker
Security & Data
Secure REST APIsAuth0AWS KMSPostgreSQLMongoDB
Engineering Practices
TDDBDDAgile DeliveryRegulated Environments
Frontend
TypeScriptNode.jsReactCSS
Other Technologies
C, C++C#, .NETRuby, RailsPHP, Laravel
Accolades & Certifications
AWS Certified Cloud Practitioner (CLF-C02)
LFC131: Green Software for Practitioners
Excellence Scholarship for Education
DWP Project Award Nomination
Education
BSc Computer Science, First-Class Honours (80%)
Swansea University