theWhisk.dev

William Smallman-Köpf

william@thewhisk.dev · thewhisk.dev · github.com/theWhisk · linkedin.com/in/theWhisk

Profile

Backend engineer specialising in distributed, event-driven Java systems in high-ownership environments, owning end-to-end implementation of greenfield microservices and implementing practices adopted organisation-wide. Domain experience spans payments and financial flows. Values solid engineering fundamentals whilst leading AI-native SDLC initiatives on my team, adopting agentic tooling and hosting an internal podcast with principal engineers and architects on building effectively with AI.

Experience

Software Engineer — Sage, Barcelona

October 2025 – Present · Backend engineer on a payments team.

Backend engineer on a payments team.

  • Built an AppSync/GraphQL API for a new UI, acting as an authentication proxy between client applications and backend services via the micro-frontend.
  • Drove a technical-debt reduction effort on services carrying significant legacy burden, building the case for systematic modernisation over reactive patching.
  • Selected as an AI Catalyst driving practical AI-native development across teams and repositories, built agentic tooling for review and refactor of brownfield code, including a test-analysis agent that validates test quality, closes gaps and extends coverage..
  • Created and host an internal engineering podcast on adopting AI in engineering, interviewing senior technical staff including the principal architect; recognised by leadership and expanding into an ongoing series.

Software Engineer — PhoenixNAP, Malta

June 2022 – September 2025 · PhoenixNAP’s Bare Metal Cloud is an automated dedicated-server platform; I worked across the payments and integration services behind it.

  • Built a Google Ads integration microservice from the ground up, implementing GDPR-compliant conversion attribution and Micrometer/Prometheus metrics to reconcile reported figures.
  • Built and owned a new accounting microservice from inception, extracting invoicing from a payments service into its own domain to clarify separation of concerns.
  • Primary maintainer of core payments service, contributing to the initial build and knowing it inside out.
  • The team’s go-to for Temporal (workflow-orchestration tool), sharing knowledge and proposing a replay testing approach that eliminated determinism exceptions which was adopted company-wide.
  • Recognised by engineering leadership through maximum increases across successive reviews and an out-of-band exception above the standard range.

Full-Stack Developer — Colonel Duck, Birmingham

May 2021 – May 2022 · Colonel Duck built PreEnrolment, enrolment training and data onboarding software for construction companies.

  • Hired to replace two departing developers; became the sole developer within six weeks and took full ownership of the product across frontend, backend and customer-facing work.

Selected Projects & Community

  • Unwave Network — Personal project inspired by record collecting, exploring music-adjacent software tooling. (unwave.net)
  • MEIA — Memberships & Payments (Freelance, 2025) — Built memberships and payments functionality for the Malta Entertainment Industry and Arts Association.
  • Devs in Malta Community (2025) — Co-organised developer meetups; ran independent events and gave a talk at a dev disasters evening.
  • EdX Bootcamp Teaching Assistant (2022) — TA for a React bootcamp; supported students through coursework and projects.
  • Lykelli (Volunteer, 2021) — Contributed to a non-profit building technology to improve wellbeing.

Skills

Languages & Frameworks: Java 21, Spring Boot Distributed Systems: RabbitMQ, REST APIs, Temporal AI Practice: Context engineering Data: MongoDB, PostgreSQL, MySQL Delivery & Testing: CI/CD, unit & integration testing Architecture: Cloud-native microservices, event-driven systems

Education

Diploma of Higher Education — Computing & IT Open University (UK) · 2012–2016

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