Oussama Gounaya · Paris, France

Senior Fullstack Engineer | DevOps

The engineer who ships fast, builds clean, and owns the full stack — from API to deployment.

NestJS · React · GraphQL

7+ years of experience50,000+ users served2M daily active users5 enterprise clients

About

I am Oussama Gounaya, a Senior Fullstack Engineer | DevOps based in Paris, France. I help organizations ship reliable products fast, from API architecture to cloud deployment.

Beyond delivery, I taught web development and programming at INSY2S, AFPA, UPHF and ECOLE-IT, supporting 50+ students through labs, exams and project mentoring (16 student pairs).

Currently available for freelance missions

Languages: French (C2), Arabic (C2), English (B2), Spanish (A2)

End-to-end ownership from product discovery to production deployment

Architecture mastery: Monorepo Nx, CQRS, BFF, event-driven microservices

Quality first: Jest, Cypress, Playwright, Cucumber, SonarQube on PR

AI-enabled delivery: Copilot Agents, automated QA generation, review assistants

Education

• Master in Computer Science, Engineering & Innovation (2018–2020)
• Master in New Information Systems & Decision-Making Technologies
• Bachelor in Computer Science (2015–2018)

Selected Case Studies

Sept 2025 – present

Leroy Merlin

Centralize and secure access to strategic group data across multiple business teams.

• Built scalable NestJS services with complex GraphQL resolvers
• Enabled async communication through Kafka event-driven architecture
• Delivered CI/CD with GitHub Actions, Docker, Kubernetes + Vault

TypeScriptNestJSGraphQLVue.jsKafkaPostgreSQLRedisKubernetesVaultJestCucumber

Jan 2021 – Sept 2025

AXA

Modernize and scale insurance subscription flows for a large European insurer.

• 50,000+ clients on platform
• 30% reduction in subscription time
• 25% fewer production incidents via Cypress e2e pipeline

ReactNext.jsAngularTypeScriptNode.jsNestJSCypressPlaywrightAWSAzure

Dec 2018 – Aug 2020

Carrefour

Rebuild loyalty app to be fully responsive and scalable across all devices.

• 2,000,000 daily active users
• Led full migration to React in 10 months
• Introduced BFF architecture for optimized UX

ReactNext.jsTypeScriptNode.jsExpressAzure DevOpsSonarQube

Dec 2018 – Aug 2020

Auchan Russia

Build a responsive multi-device stock management interface.

• Developed REST APIs with MVC architecture
• Implemented dynamic filters, pagination, lazy loading
• Built rich data visualizations with D3.js and Chart.js

Node.jsMySQLReactChart.jsD3.js

Experience

Leroy Merlin

Fullstack & DevOps Engineer · Villeneuve-d'Ascq, FR

Sept 2025 – present

Building internal data platforms in a microservices environment with event-driven architecture (Kafka, Kubernetes, NestJS).

NestJSGraphQLKafkaKubernetes

AXA

Senior Software Engineer · Paris, FR

Jan 2021 – Sept 2025

Shipped P&C subscription platforms for 50,000+ clients, led Angular→React migration and introduced AI-assisted development workflows.

ReactNext.jsNestJSCypressPlaywright

ShadowBreak

Fullstack Developer · London, UK

Aug 2020 – Dec 2020

Worked on satellite image retrieval and GEOINT pipelines with frontend performance optimization (lazy loading, caching, compression).

ReactNode.jsGeo data

Capgemini

Software Engineer · Lille, FR

Dec 2018 – Aug 2020

Delivered Carrefour (2M DAU loyalty app, React migration) and Auchan Russia missions (stock platform, backend APIs).

ReactNode.jsAzure DevOpsSonarQube

Jagger & Lewis

Fullstack Developer · Roubaix, FR

Sept 2018 – Dec 2018

Built iOS/Android apps with React Native and ML workflows (TensorFlow/Python) for pet behavior anomaly detection.

React NativePythonTensorFlow

Fit Retail

Software Engineer (Internship) · Lille, FR

Apr 2018 – Aug 2018

Worked on PLM/ERP integration for Kering and Kiabi, SQL Server optimization and a responsive React + Node.js application.

ReactNode.jsSQL Server

Skills & Activity

Frontend

ReactNext.jsVue.jsAngularReact NativeFlutterReduxReact QueryTailwindCSSMaterial UIShadcnFramer MotionD3.jsRechartsStorybook

Backend

Node.jsNestJSExpress.jsPythonGraphQLREST APIOpenAPI GeneratorKafka

DevOps & Cloud

DockerKubernetesGitHub ActionsJenkinsTerraformAWSAzureVercelSupabaseJFrogVaultSonarQubeElasticsearchAiven

Databases

PostgreSQLMySQLMongoDBRedisSQL Server

Testing & Quality

JestReact Testing LibraryCypressPlaywrightCucumberSwaggerESLintPrettierMockttp

Data & AI

TensorFlowJupyterPandasNumPyMatplotlibCopilot AgentsAI QA automationLLM prompting

GitHub Contributions

View profile

github.com/Gounaya

LessMore

Let's build your next product

Available for freelance and long-term product missions ($55–120/hr). Based in Paris, France.

o.gounaya@gmail.com Book a call

Usually responds within 24h · Medium: medium.com/@ogounaya