Alejandro Reyes
Verified Expert in Engineering
Full-stack Developer
New York, NY, United States
Toptal member since March 10, 2026
Alejandro is a full-stack engineer with 9+ years of experience building scalable SaaS enterprise applications serving thousands of monthly users. He has served in several industries, including healthcare, automobile, aviation, real estate, and change management. He excels in Python, React Native, and Ruby on Rails, leading projects that enhance user engagement and system reliability. Notably, Alejandro led the design of a healthcare application that improved caregiver engagement by 48%.
Portfolio
Experience
- JavaScript - 9 years
- Ruby on Rails (RoR) - 9 years
- React Native - 4 years
- Node.js - 4 years
- TypeScript - 4 years
- Python - 4 years
- Amazon Web Services (AWS) - 2 years
- Large Language Models (LLMs) - 1 year
Preferred Environment
Python, React Native, Ruby on Rails (RoR), Amazon Web Services (AWS)
The most amazing...
...project I've been part of is leading the design and delivery of a healthcare greenfield application that improved caregiver engagement by building a RAG system.
Work Experience
Senior Full-stack Engineer
LaunchPad Lab
- Led engineering across 5+ concurrent client engagements, delivering 10+ production AWS applications in Ruby on Rails and React/TypeScript on time and within scope.
- Owned the reliability and scalability of a high-traffic Ruby on Rails platform on AWS serving 25,000+ monthly users, maintaining 99.9% uptime, proactively addressing performance bottlenecks, and reducing production issues by 80%.
- Drove the design and delivery of a healthcare greenfield application that improved caregiver engagement and service quality by combining behavioral incentives with AI-powered insights (RAG system), reducing caretaker incident reports by 48%.
- Served as technical lead across client engagements, mentoring teams of 3-5 engineers and establishing architectural standards that reduced onboarding ramp-up time for new developers by 60%.
Full-stack Engineer
ThumbStopper
- Built and launched the company's first mobile application in React Native, delivering a key asset used by the sales team to expand platform reach to mobile prospects.
- Developed the company's first client onboarding form builder using React/TypeScript, Rails, and Stripe, enabling 3+ new client sign-ups per week and significantly accelerating the sales conversion pipeline.
- Modernized a legacy QuickBooks Web Connector integration, migrating to AWS and Ruby on Rails to improve reliability and maintainability.
Developer
Code Castle
- Maintained and improved client applications using Ruby on Rails, PostgreSQL, MySQL, and JavaScript, progressing from intern to developer within the first year.
- Contributed to agile project planning and delivery, helping the agency expand its client portfolio through consistent, quality execution.
- Met with stakeholders and client prospects to provide technical guidance on efforts.
Web Developer
TELUS International
- Developed core social features, including sharing, post interactions, and bug resolution, for the company's internal social media platform serving employees across 10+ global call centers using React and a RESTful API built in Ruby on Rails.
- Contributed to agile project planning and delivery, helping the agency expand its client portfolio through consistent, quality execution.
- Designed and built a custom emoji module using React and Ruby on Rails, deployed across the company's global call center network spanning the Americas, Europe, and Asia-Pacific, increasing employee engagement and daily platform usage.
- Partnered with a DBA to migrate the company's database to Google Cloud, coordinating across global stakeholders and ensuring zero data loss during transition.
Experience
Care Taker Analysis App for a Healthcare Company
Project Management Marketplace
https://www.pmaashub.comEducation
Certificate in Computer Science
Lambda School - United States
Associate's Degree in Computer Science
ITCA - El Salvador
Skills
Libraries/APIs
React, REST APIs, Node.js, SQLAlchemy, Vue
Tools
Expo
Languages
Python, JavaScript, TypeScript, Ruby, GraphQL
Frameworks
React Native, Next.js, Ruby on Rails (RoR), Agentic Frameworks
Platforms
Amazon Web Services (AWS), Firebase, Amazon EC2, Docker, Android, iOS, Azure, Google Cloud Platform (GCP)
Storage
PostgreSQL, MySQL, Amazon S3 (AWS S3), MongoDB, SQL Stored Procedures, Google Cloud
Other
Software Deployment, Software Development, Supabase, Authentication, CI/CD Pipelines, Push Notifications, FastAPI, Error Logging, Algorithms, API Integration, APIs, Full-stack Development, Integration, Cloud, Mobile First, Technical Leadership, Full-stack, Amazon RDS, Large Language Models (LLMs), RAG Systems, App Store, Google Play Store, In-app Purchases, AI Agents, Artificial Intelligence (AI)
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