Backend Engineer with 3 years of experience building scalable backend systems and RESTful APIs for web and mobile applications. Skilled in Java, Spring Boot, Kotlin, Node JS, Typescript, Golang, and microservices. Experienced in healthcare, IoT, AI, and social domains, building secure and high-performance systems.

• Email: duyphi2011@gmail. com
• LinkedIn: Phi Duy

• Da Nang University of Science and Technology
  Bachelor in Information Technology (Oct 2020 - Sep 2024)
  GPA: 3.79/4.0

• CodeGym Da Nang
  Java Bootcamp Course (Dec 2021 - Dec 2022)

Languages & Frameworks:

• Java, Spring Framework, Spring Boot, Kotlin, Golang, Echo Framework, Node.js, NestJS, Express.js

Databases:

• PostgreSQL, Redis, ORM (Hibernate, Exposed, Bun ORM, Prisma, Kysely)

DevOps & Cloud:

• Docker, Kubernetes, Jenkins, Terraform, AWS (S3, ECS, SQS, CloudWatch, Rekognition), Datadog, DigitalOcean

APIs & Integrations:

• Twilio, OpenAI, Stripe, Google APIs, Apple Pay, Google Pay, Google Analytics, Agora SDK, Video SDK, Comet Chat

Security:

• Spring Security, JWT Authentication

Testing & Tools:

• Git, Gradle, JUnit, Spring Boot Test, Integration Testing

Languages:

• English (TOEIC 785) - Professional communication skills with experience working in US and Germany-based companies

Software Engineer | July 2025 - Present

Project: STBK – German Tax Consultant Chamber Portal

• Team Size: 15 members
• Description: A large-scale digital platform for German citizens to submit applications, post job offers, and register as tax consultants, built with a modular microservices architecture.

Responsibilities:

• Developed and maintained core backend services for form submission, job posting, and application processing
• Implemented features such as CRUD admin management, job transfer, email notifications, Excel exporting, and scheduled tasks
• Collaborated closely with frontend developers, QA engineers, and business analysts to clarify requirements and ensure quality
• Performed unit testing, integration testing, and code reviews to ensure code quality
• Built and maintained CI/CD pipelines with Jenkins and managed Kubernetes deployments

Technologies: Java, Kotlin, Spring Boot, Spring Data JPA, JUnit, PostgreSQL, Jenkins, Kubernetes

Software Engineer | June 2023 - July 2025

Built and maintained backend systems for multiple U.S.-based startups across AI, CRM, IoT, and dating platforms.

Key Achievements:

• Implemented JWT authentication using Spring Security
• Improved system performance through query optimization, caching, and debugging
• Supported system monitoring, handled on-call responsibilities
• Contributed to infrastructure improvements using AWS and Terraform

Intern Backend Developer | Jan 2023 - June 2023

• Gained hands-on experience in backend development using NestJS and Node.js
• Contributed to small-scale projects in e-commerce, IoT, and mobile applications
• Strengthened understanding of API design, database interaction, and code maintainability

Team: 8 members

Description: A healthcare platform leveraging AI and LLMs to enhance patient care and automate workflows.

Responsibilities:

• Developed REST APIs for care navigation, provider management, and patient interaction
• Implemented APIs for user, group, feature flag, and revenue management modules
• Implemented Twilio messaging and analytics tracking to monitor engagement and usage
• Ensured API security using Spring Security + JWT

Technologies: Java, Spring Boot, JUnit, OpenAI, PostgreSQL, Terraform, Twilio, Datadog

Team: 12 members

Description: A distributed IoT system for managing EV charging stations and real-time operations, with a rental service for chargers.

Responsibilities:

• Built and maintained backend services using Kotlin and Java, with a focus on system performance, scalability, and reliability
• Implemented APIs for user management, group management, feature flag management, and revenue management
• Built rental and payment processing systems
• Collaborated with the mobile team
• Implemented authentication and authorization using Spring Security and JWT
• Supported deployment, monitoring, and debugging of production systems
• Ensured data consistency and system reliability

Technologies: Java, Spring Boot, Kotlin, PostgreSQL, Terraform, AWS, Datadog

Team: 9 members

Description: A dating platform making connections with people around the world with over 100K users.

Responsibilities:

• Developed backend services and exposed APIs to support various application functionalities, including integration testing
• Integrated third-party services, including AWS Rekognition for face verification and payment gateways (Google Pay, Apple Pay) for in-app purchases
• Implemented image upload features and supported mobile site integrations
• Collaborated on transitioning parts of the back-end system from Node.js to Golang to enhance efficiency
• Implemented core features including subscription management, matching suggestions, and face verification
• Optimized SQL queries to improve API performance for retrieving matching suggestions

Technologies: Golang, Echo Framework, PostgreSQL, Redis, AWS Rekognition, Google Pay, Apple Pay

Team: 6 members

Description: A comprehensive CRM system backend tailored for wellness spa professionals, integrated with healthcare functionalities.

Responsibilities:

• Developed backend services and APIs for charting and patient data management
• Implemented communication workflows and campaign management using Twilio
• Led data migration from legacy platforms using CSV/ZIP uploads processed via AWS SQS and background workers
• Developed CRUD APIs and integrated them with client applications to deliver end-to-end features

Technologies: TypeScript, Express.js, PostgreSQL, Redis, AWS (SQS, S3, CloudWatch), Twilio

Team: 8 members

Description: Developed a feature flag SDK to enable or disable features dynamically without modifying the source code or requiring redeployment.

Responsibilities:

• Developed backend services and exposed APIs for feature management
• Built a Kotlin SDK and authored comprehensive documentation
• Enabled teams to control feature rollouts and A/B testing without deployments

Technologies: Kotlin, Spring Boot, PostgreSQL

Team: 6 members

Description: Developed a livestream platform that enables users to communicate, share content, chat, and build connections.

Responsibilities:

• Served as a Backend Engineer, integrating third-party services for livestreaming and chat functionalities
• Implemented payment features using the Stripe payment gateway
• Conducted testing to ensure the project met quality standards and functionality
• Built APIs for user interactions and content management

Technologies: Kotlin, Spring Boot, Agora SDK, Stripe, PostgreSQL

Team: 2 members

Description: An interactive backend system for an English learning platform, supporting livestream rooms, AI conversations, translation, and vocabulary exercises.

Responsibilities:

• Developed the backend services, integrating third-party services such as Video SDK, OpenAI, Comet Chat, and Google Speech-to-Text and Text-to-Speech APIs
• Deployed the backend service on DigitalOcean
• Authored comprehensive documentation for the project
• Built real-time communication features and AI-powered learning APIs
• Integrated OpenAI API to enable AI conversation features
• Deployed the application to DigitalOcean, using Docker for containerization
• Managed database with PostgreSQL and Prisma ORM

Technologies: TypeScript, NestJS, PostgreSQL, Prisma, Docker, DigitalOcean, OpenAI API, Comet Chat, Video SDK, Google Speech-to-Text, Google Text-to-Speech, Google Cloud Storage

Team: 5 members | University PBL

Description: Developed a pharmacy management system to help clients easily find and purchase pharmacy products.

Responsibilities:

• Developed backend services using Spring Boot, covering functionalities such as authorization, employee management, customer management, product management, and order management
• Conducted thorough testing and authored documentation for the project
• Implemented secure authentication and role-based access control

Technologies: Java, Spring Boot, PostgreSQL

• API design and RESTful architecture
• Spring Security and JWT authentication
• SQL optimization and query performance
• Clean code and design patterns
• Team collaboration and communication
• Microservices architecture
• Cloud infrastructure and DevOps
• Third-party service integration
• Payment gateway integration (Stripe, Apple Pay, Google Pay)
• Real-time communication systems
• AI/ML API integration
• Database optimization and caching

💼 Open to opportunities in backend engineering, microservices, and system design

📧 Feel free to reach out:

• Email: [email protected]
• LinkedIn: Phi Duy
• GitHub: @duyle2002