Looks like you have JavaScript disabled. For the full Twine experience, you will need to re-enable it.

Hello, I'm Charles Walls—a Senior Full Stack Engineer with 10+ years of experience designing and deploying secure, scalable booking and reservation platforms for SaaS, e-commerce, and transportation industries. I excel at turning complex requirements into robust, user-friendly solutions. I partner closely with product and security teams to reduce errors, boost uptime, and deliver a great experience for customers and operators alike.…Hello, I'm Charles Walls—a Senior Full Stack Engineer with 10+ years of experience designing and deploying secure, scalable booking and reservation platforms for SaaS, e-commerce, and transportation industries. I excel at turning complex requirements into robust, user-friendly solutions. I partner closely with product and security teams to reduce errors, boost uptime, and deliver a great experience for customers and operators alike.

Charles Walls

Full Stack Developer, Back-End Developer, Front-End Developer, +3





Hello, I'm Charles Walls—a Senior Full Stack Engineer with 10+ years of experience designing and deploying secure, scalable booking and reservation platforms for SaaS, e-commerce, and transportation industries. I excel at turning complex requirements into robust, user-friendly solutions. I partner closely with product and security teams to reduce errors, boost uptime, and deliver a great experience for customers and operators alike.…Hello, I'm Charles Walls—a Senior Full Stack Engineer with 10+ years of experience designing and deploying secure, scalable booking and reservation platforms for SaaS, e-commerce, and transportation industries. I excel at turning complex requirements into robust, user-friendly solutions. I partner closely with product and security teams to reduce errors, boost uptime, and deliver a great experience for customers and operators alike.

Available to hire

Hello, I’m Charles Walls—a Senior Full Stack Engineer with 10+ years of experience designing and deploying secure, scalable booking and reservation platforms for SaaS, e-commerce, and transportation industries.

I excel at turning complex requirements into robust, user-friendly solutions. I partner closely with product and security teams to reduce errors, boost uptime, and deliver a great experience for customers and operators alike.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Intermediate

Intermediate

Intermediate

Language

English

Fluent

Work Experience

Senior Full Stack Developer at SyenApp

January 1, 2023 - Present

Designed and deployed a real-time booking system for a multi-vendor marketplace, enabling 100K+ monthly users to view availability, reserve services, and receive instant confirmations; improved booking accuracy by 45%. Implemented Stripe and PayPal payment gateways with PCI DSS compliance; tokenization and encryption.

Senior Front End Developer at Apple

December 1, 2022 - September 11, 2025

Led the frontend development of an internal booking/reservation platform supporting device labs and AI/ML compute resources; enabled 200K+ internal users to reserve infrastructure with real-time availability tracking. Built Python/Django and FastAPI services with PostgreSQL to handle millions of reservations per month with 99.9% uptime.

Senior Developer at WiseTech Global

November 1, 2020 - September 11, 2025

Built backend scheduling and booking engine used by global logistics clients; ensured 99.99% uptime. Created Node.js and Java Spring microservices; designed GraphQL/REST APIs; developed driver and fleet dashboards for itinerary scheduling and revenue insights; improved dispatch efficiency by 30%.

Full Stack Developer at Trio Workforce Solutions

February 1, 2018 - September 11, 2025

Built a healthcare appointments scheduling and booking system with Python/Django and Node.js REST APIs; supported thousands of professionals and candidates daily. Implemented responsive booking flows, partitioned SQL schemas, and admin dashboards; improved hiring engagement by 35%.

Senior Full Stack Developer at Syena App

January 1, 2023 - Present

Senior Front End Developer at Apple

December 1, 2022 - September 11, 2025

Led front-end development of an internal booking/reservation platform supporting device labs and AI/ML compute resources, enabling 200K+ internal users to reserve infrastructure in real-time.

Senior Developer at WiseTech Global

November 1, 2020 - September 11, 2025

Led backend development of transport scheduling and booking engine used by global logistics clients, handling millions of shipment reservations daily. Built Node.js and Java Spring Boot microservices for real-time reservation workflows; achieved 99.99% uptime during peak booking surges. Architected GraphQL APIs to power customer booking portals and dispatch dashboards; reduced integration time for new clients by 50%. Implemented PostgreSQL and MySQL schemas with partitioning and indexing strategies; improved query performance by 55% and supported global scaling.

Full Stack Developer at Trio Workforce Solutions

February 1, 2018 - September 11, 2025

Built a healthcare appointment scheduling and booking system using Python/Django and Node.js APIs; designed responsive booking flows in React and Angular; implemented PostgreSQL schemas with partitioning and indexing; improved engagement by 35%; enabled recruiters to manage candidate interviews and resources with automated workflows.

Senior Full Stack Engineer at SyenApp

January 1, 2023 - Present

Senior Front End Developer at Apple

December 1, 2022 - September 11, 2025

Led frontend and backend improvements for internal booking platforms, built responsive React front-end dashboards, integrated payment gateways (Stripe, PayPal), improved accessibility and performance, and implemented observability and security best practices.

Senior Developer at WiseTech Global

November 1, 2020 - September 11, 2025

Developed transportation scheduling and booking engine used by global logistics clients, handling millions of shipment reservations daily; built Node.js and Java Spring Boot microservices for real-time workflows; designed PostgreSQL schemas; containerized with Docker; implemented dashboards and payment integrations.

Full Stack Developer at Tri o Workforce Solutions

February 1, 2018 - September 11, 2025

Built healthcare appointment scheduling and booking system with Python/Django and Node.js APIs; developed responsive booking flows in React and Angular with real-time calendar integrations; designed PostgreSQL and SQL Server schemas; integrated PCI DSS-compliant payment solutions; automated confirmations, reminders, and cancellations; created fleet-like scheduling dashboards; automated deployments on Azure with Docker and Kubernetes; mentored interns and junior developers.