About Sebastien
Senior backend and cloud engineer operating via a UK limited company. I specialise in designing and building backend systems, APIs, and SaaS platforms using Python and Java (Spring Boot), with a strong focus on cloud-native, production-ready architectures.
I’ve delivered backend platforms for mobile and web applications, including authentication, offline support, payment integration, and automation. Experienced in AWS services (Lambda, EC2, S3, RDS), distributed systems, and scalable multi-tenant platforms.
I own projects end-to-end, from architecture and development through deployment, scaling, and live operations. Currently developing additional SaaS and mobile applications focused on real-time performance and operational efficiency.
English
Native or bilingual
French
Native or bilingual
Can work on-site
London (up to 50km)
Experience
- Auto Scripts Integration LimitedSenior Backend & Cloud EngineerSeptember 2023 - Today (2 years and 9 months)Hatfield, United Kingdom•Designed, built, and released a production SaaS mobile application (Android) on Google Play (released 17 February 2026)•Architected and delivered a full-stack platform:oBackend: Python (Flask), MySQLoMobile: React Native with SQLite (offline-first sync architecture)oCloud: AWS (RDS, EC2, S3, SES, SNS, SQS, Secrets Manager)•Designed and implemented secure authentication, token management, and multi-tenant API architecture•Built offline-first data synchronisation between mobile clients and cloud backend•Developed additional platform services using Java (Spring Boot), AWS Cognito, Lambda, MongoDB, and Stripe integration•Owned full lifecycle delivery: architecture, infrastructure provisioning, CI/CD, deployment, and production monitoring•Currently designing and developing a second mobile application focusing on:oreal-time event systemsodynamic difficulty scalingoperformance-optimised renderingogameplay loop and engagement system design
- bigsparkLead Software EngineerJuly 2021 - September 2023 (2 years and 2 months)• • Led backend development for a production event ticketing platform, working with Java Spring Boot, AWS, and distributed systems.• • Designed and implemented microservices and business rules using Kafka, Red Hat Decision Manager, and Java.• • Integrated blockchain-based components using Hedera Hashgraph APIs and Solidity.• • Managed CI/CD pipelines, server installations, and coordinated releases across multiple Bitbucket repositories.• • Worked closely with product and delivery teams to translate business requirements into scalable technical solutions.
- FreemanBusiness Systems Analyst / Automation EngineerApril 2018 - July 2021 (3 years and 3 months)• • Automated enterprise business workflows using Python and AWS (Lambda, RDS, EC2, S3, DynamoDB).• • Built SQL-based reporting and data-processing solutions to support operational and financial decision-making.• • Developed VBA automation and Excel-based tooling for internal business intelligence dashboards.• • Delivered training and documentation for enterprise IT systems and automated workflows.
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Education
- BSc (Hons) Open Degree –The Open UniversityBSc (Hons) Open Degree –
- & BusinessUniversity of Hertfordshire& Business