From architecture to UI: fullstack expert in crafting resilient, high-performance web platforms. Mastering modern frontend frameworks (React, Vue, Solid, Angular), robust backend stacks (Node.js, Spring), and scalable system design
Contact : kevin.pennarun@gmail.com
About Kevin
With 13 years of experience in software engineering, I specialize in designing and delivering robust, scalable web platforms across the full stack. My background spans multiple industries, public sector, finance, cybersecurity, healthcare, and retail, giving me a broad perspective on product and technical challenges.
Expertise
Technical architecture: Design of scalable, high-performance systems aligned with product and team needs.
Full-stack development: Mastery of modern frontend frameworks (React, Vue, Solid) and backend platforms (Node.js, Spring, Kotlin), with a strong focus on end-to-end quality.
Tech stack evolution: Continuous modernization of legacy systems to improve maintainability, performance, and developer experience.
Team collaboration: Experienced in working within cross-functional product teams, mentoring engineers, and driving engineering excellence.
Engineering values
Code quality: Emphasis on clean architecture, testability, and long-term maintainability.
Delivery focus: Pragmatic and iterative approach to building software that ships.
Adaptability: Ability to quickly ramp up in new environments and domains.
My experience as a tech lead enables me to align engineering efforts with business goals, lead initiatives from concept to production, and help teams scale their practices as well as their systems.
Experiences
Lead Full-Stack Engineer - Freelance
As part of Carrefour Links Growth, a project to collaborate around Carrefour data
Built a green-field analytics webapp from concept to production. Co-designed a security-by-design, cloud-native architecture adopted as the new standard across the Carrefour Links ecosystem
Unlocked sub-3-second insights on 10 billion+ retail transactions—replacing minute-long KPI loads with a modern, responsive SPA
Delivered MVP to beta in 8 weeks. After a 7 weeks discovery & architecture phase, interviewing experts and executives, translated theory into code, shipped on schedule, and iterated based on real-world feedback
Scaled to 3 countries and thousands of users. Hardened the platform, and orchestrated a phased roll-out to internal teams and external customers
Embedded observability end-to-end. Integrated Sentry (alerts, tracing, ...) across front & back-end, collaborating directly with Sentry.io engineers to tailor monitoring to Carrefour’s constraints
Multiplied impact across squads. Mentored engineers and supported other project teams re-using the architecture, accelerating delivery of future Carrefour Links products.
Stack:
TypeScript / Node.js / Vue.js / Fastify / tRPC / Tailwind CSS / PostgreSQL / Casbin / GCP (Cloud Run, Cloud Functions, PubSub, Cloud SQL, ...) / Looker / Sentry
Product & Full‑Stack Lead - Freelance
Designed and shipped the SaaS platform powering JUSTPLAYFAIR’s bias‑free talent recruitment, training, and promotion methodology
Built and managed a cross‑functional product squad (UI/UX designer & product manager)
Collaborated directly with the founder to translate vision into incremental releases in production
Established a modern TypeScript & React stack with monorepo and automated CI/CD, enabling rapid, reliable iterations
Technologies :
Typescript / Firebase / GraphQL / Koa / PostgreSQL / ReactJS / Storybook / Tailwind CSS
FullStack Typescript developer - Freelance
As part of a major evolution of the Jackpot API. I designed and developed the back-office to operate the Jackpot service
Designed and built a modular back‑office to operate the Jackpot service, extending the offering beyond gift cards
Introduced a TypeScript monorepo with React 18, React Query, React Hook Form, and Tailwind CSS, paired with Nest.js on the server side
Automated GCP infrastructure with Pulumi (IaC), establishing a unified, repeatable CI/CD pipeline
Translated a complex business domain into a smooth user experience
Technologies :
TypeScript / Pulumi / Nest.js / ReactJS / Tailwind CSS
UI React.js developer - Freelance
Implementation of the Dolead Design System in Storybook and embedded them into flagship lead‑gen apps.
Supported multiple product squads in migrating legacy UIs, boosting feature delivery speed and ensuring visual consistency
Technologies :
TypeScript / ReactJS / Storybook / Tailwind CSS