John Lester Serrano

Full-Stack Developer

+64223558198johnlesterserrano1@gmail.com8 Warbler Crescent, Papakura 2110, Auckland, NZ

Experience

Lead Full-Stack Developer

Lubin AI LLC

11/2025 – PresentWashington, USA

Designed and implemented scalable APIs using AWS API Gateway, AppSync, Lambda, VPC, CloudFront, S3, and Cognito, with DynamoDB and OpenSearch supporting application data and search.
Architected and managed AWS infrastructure with CloudFormation, reducing manual deployment effort and improving environment consistency.
Integrated Claude APIs to power in-app chat for task support, user assessments, and health passport assistance.
Built AI agents and reusable skills to streamline development workflows and speed up testing.
Trained AI models for task-specific use cases to improve relevance and response quality.

Lead Full-Stack Developer

Moji Social LLC Inc

04/2023 – 2025Washington, USA

Designed and implemented scalable APIs using AWS API Gateway, Lambda, VPC, CloudFront, S3, and Cognito, integrating RDS and OpenSearch for data storage and search.
Architected and managed cloud infrastructure with AWS CloudFormation, reducing manual backend deployment time and ensuring consistent provisioning.
Collaborated with UI/UX designers in Figma and integrated product analytics via Firebase, Segment, and Branch.io to drive data-informed decisions.
Automated mobile deployment to the App Store and Google Play using Expo, and integrated OpenAI APIs for intelligent in-app suggestions.

Lead Software Engineer

HealthnowPH/KonsultaMD

03/2022 – 03/2024Makati, Philippines

Led a team of 4 engineers building a scalable cross-platform mobile application with React Native and Expo, deployed to both iOS and Android.
Architected a scalable, serverless backend using AWS Lambda, API Gateway, OpenSearch, VPC, Cognito, CloudFront, and S3 to support real-time features and thousands of concurrent users.
Managed iOS and Android certificates and provisioning profiles, resolving signing issues and ensuring smooth app releases.
Integrated CI/CD pipelines using AWS CodeCommit and automated deployment to improve release velocity.

DevOps Developer

SquidPay

05/2022 – 02/2023Pasig, Philippines

Managed and optimized AWS EC2 and ECS (Fargate) instances, resolving server issues to ensure high availability and reliability.
Improved and maintained CI/CD pipelines, accelerating deployment cycles and reducing downtime.
Optimized network traffic distribution using AWS Load Balancer, improving application scalability and performance.

Software Engineer

Apppps Partners Inc

04/2019 – 03/2022Quezon City

Developed and deployed RESTful APIs using AWS API Gateway, Lambda (Node.js), VPC, and Cognito, enabling a secure and scalable microservices architecture.
Built responsive frontend web applications using ReactJS, Bootstrap, jQuery, and HTML/CSS with cross-browser compatibility.
Automated infrastructure provisioning with AWS CloudFormation, managing stacks for repeatable deployments across staging and production.
Optimized data flows and API performance, reducing backend response time and improving user interaction.

DevOps Developer

Sun Moon Technologies

11/2021 – 02/2022Manila, Philippines

Resolved critical server issues, improving system stability and uptime.
Integrated and managed server upgrades using AWS EC2, enhancing infrastructure performance and security.
Optimized network traffic distribution with AWS Load Balancer, ensuring scalability and improved performance.

DevOps Developer

Forent

07/2021Makati City, Philippines

Developed a CRUD management system featuring tax computation, salary and benefits management, attendance tracking, and file uploads.
Built RESTful APIs using the CakePHP framework to power backend services and dynamic client data interactions.
Implemented the frontend with Bootstrap, jQuery, JavaScript, and HTML for rapid development and seamless backend integration.

Frontend Developer

Apppps Partners Inc

10/2018Quezon City, Philippines

Built responsive, dynamic interfaces using JavaScript with the Laravel framework.
Integrated RESTful APIs with Laravel controllers and frontend components to handle real-time user interactions.
Collaborated with backend teams to define API contracts, validation rules, and middleware for secure data flow.

Web Developer Intern

Apppps Partners Inc

03/2018Quezon City, Philippines

Used AJAX to enable dynamic data loading and smoother front-end interactions without requiring full page reloads.
Created and maintained responsive page layouts using CSS3 and Bootstrap 4.
Supported the development of business websites using Laravel.

Summary

Full-Stack Developer and AI Engineer with 7+ years of experience building scalable web and mobile applications and serverless AWS infrastructure. Strong across React, React Native, Next.js, Node.js, and Python, with deep expertise in cloud architecture, CI/CD automation, and production AI/LLM integrations. Delivering secure, reliable software that supports real-world product growth.