Available for opportunities
Hi, I'm
Bettahar Samir
Software Engineer
Full-stack software engineer specialized in modern web and mobile application development with React, React Native, Next.js, TypeScript, and Tailwind CSS. Experienced in designing and integrating REST APIs using NestJS and Fastify, implementing authentication, and building fast, maintainable, and user-friendly interfaces.
Work Experience
Full-Stack Engineer
ObserveOne
Nov. 2025 – Present
Remote
- Led the migration of a monolithic Express.js backend to a scalable Service-Oriented Architecture (SOA), decoupling core services like `apiCheck` and `browser` into a dedicated Data Access Layer (DAL).
- Architected and optimized a high-performance Next.js dashboard, implementing real-time updates via SSE and refactoring complex UI components for improved maintainability.
- Developed a robust TypeScript CLI tool for automated monitoring management, featuring secure authentication flows and direct API integration.
- Engineered a comprehensive testing infrastructure using Vitest and Playwright, achieving >80% coverage across the full stack (Frontend, Backend, and CLI).
- Designed high-volume load testing pipelines using K6 to validate system reliability under stress.
Freelance Full-Stack / Mobile Developer
Self-Employed
Sep. 2025 – Present
Remote / Algiers
- Developed mobile applications using React Native and web applications with Next.js, integrating with Fastify backend APIs.
- Built reusable and performant UI components, focusing on responsive and intuitive user experiences.
Full-Stack Developer
Omnivya
Feb. 2024 – Aug. 2025
Remote
- Designed and refactored responsive web interfaces using React, TypeScript, AstroJS, and TanStack Router.
- Built maintainable and performant UI components with Tailwind CSS.
- Developed secure authentication flows and role management with Zitadel and BetterAuth.
- Developed and optimized RESTful APIs with NestJS and Spring Boot to support SaaS frontend needs.
- Improved frontend performance and collaborated closely with product and backend teams to ensure smooth delivery.
- Implemented unit, integration, and end-to-end tests (Vitest, Playwright, TestContainers) to ensure code reliability and production quality.
Technical Arsenal
A comprehensive toolset I use to build scalable, high-performance applications.
Languages
TypeScript 
JavaScript 
Java 
Go Frontend
React.js 
Next.js React Native 
AstroJS 
SvelteKit 
Tailwind CSS Backend
NestJS 
Fastify 
Spring Boot Go (API) Database
PostgreSQL 
Spring Data JPA 
TypeORM 
Flyway DevOps & Infra
Docker 
GraalVM Auth
Zitadel 
Clerk 
BetterAuth Fastify OAuth Testing
Vitest 
TestContainers 
Playwright Observability
Prometheus 
OpenTelemetry Education
Master's in Software Engineering
University of Saad Dahlab Blida
2020 – 2022 • Blida, Algeria
Focus on software architecture, development methodologies, and full-stack development
Bachelor's in Information Systems and Software Engineering
University of Saad Dahlab Blida
2016 – 2020 • Blida, Algeria
Foundation in computer science fundamentals, algorithms, databases, and object-oriented programming.
Research & Academic Projects
Software Product Line for e-Banking Applications
Master Thesis (Java EE, Ontologies)
- Designed and developed a software product line for automatically generating e-Banking applications based on ontologies and feature models.
- Implemented a desktop configurator in Java Swing for selecting features and generating applications.
- Developed full web applications (Client and Admin portals) with Java EE (Servlets, JSP, JDBC) and deployed on Tomcat/Glassfish.
Java EE Ontologies
Java Swing 
Tomcat Parkinson's Disease Detection
Bachelor Project (Python, Machine Learning)
- Developed a medical decision support system in Python for detecting Parkinson's disease using spiral and wave handwriting tests.
- Implemented machine learning models (KNN, SVM, Random Forest) with scikit-learn, achieving up to 90% accuracy.
- Applied image preprocessing and feature extraction techniques with OpenCV, including LBP, Haralick, and Hu moments.
- Built a Tkinter GUI enabling doctors to test images and visualize confusion matrices and ROC curves.
Python 
Scikit-learn 
OpenCV Tkinter Machine Learning
Portfolio
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Get in Touch
Have a project in mind or want to discuss opportunities? Let's connect!