Senior Fullstack Developer

Lean Solutions Group; United States; On-site; USD 120,000 - 180,000; Full time

Job summary

Lean Tech seeks a Senior Full Stack Developer to design, build, and optimize modern web apps and distributed systems. You will architect scalable cloud‑native solutions, lead frontend and backend work, and drive engineering excellence with best practices.

The ideal candidate combines deep TypeScript expertise with experience in React/Next.js, Node/Express, and API design. Familiarity with AI integration, Docker, AWS, and performance profiling is highly valued.

Qualifications

• 6+ years of experience in Full‑Stack (Backend‑Frontend) TypeScript development.
• Extensive experience building scalable full‑stack applications and microservices using React, Next.js, Node.js, Express, HTML, and CSS.
• Strong knowledge of RESTful API design and OpenAPI specifications.
• Experience designing and integrating APIs, including REST and modern data‑fetching patterns.
• Extensive experience with relational DBs like MySQL or Postgres and noSQL like MongoDB/Redis.

Responsibilities

• Design, develop, and optimize modern web applications and distributed systems across the full stack.
• Architect scalable solutions and cloud‑native applications, driving engineering excellence.
• Lead and mentor teams, implement best practices, and ensure performance through profiling.
• Integrate AI agents and LLM APIs into production or near‑production systems.

Skills

TypeScript

Full‑stack

REST APIs

OpenAPI

Performance optimization

AI integration

Architectural thinking

Cloud-native

AWS

Ecommerce/retail

Tools

React

Next.js

Node.js

Express

HTML/CSS

Webpack

Docker

LLM APIs

Job description

Company Overview

Global Technology Services is a rapidly expanding organization situated in Medellín, Colombia. We pride ourselves on possessing one of the most influential networks within software development and IT services for the entertainment, financial, and logistics sectors. Our corporate projections offer a multitude of opportunities for professionals to elevate their careers and experience substantial growth. Joining our team means engaging with expansive engineering teams across Latin America, Philippines and the United States, contributing to cutting‑edge developments in multiple industries.

Position Title

Senior Full Stack Developer

Location

US

What you will be doing

We are seeking a highly skilled Senior Full‑Stack JavaScript/TypeScript Engineer to join our engineering team. In this role, you will design, develop, and optimize modern web applications and distributed systems, contributing across the entire software development lifecycle. You will play a key role in architecting scalable solutions, building high‑performance user interfaces, developing robust backend services, and driving engineering excellence through best practices and technical leadership. The ideal candidate combines deep expertise in modern JavaScript ecosystems with strong architectural thinking, AI agentic development, performance optimization experience, and a passion for building scalable, cloud‑native applications.

Required Skills & Experience

• 6+ years of experience in Full‑Stack (Backend‑Frontend) TypeScript development
• Extensive experience building scalable full‑stack applications and microservices using React, Next.js, Node.js, Express, HTML, and CSS
• Strong knowledge of RESTful API design and OpenAPI specifications
• Experience designing and integrating APIs, including REST and modern data‑fetching patterns
• Extensive experience working with relational DBs like MySQL or Postgres and noSQL like MongoDB and Redis, with a solid understanding of data modeling trade‑offs
• Familiarity with micro‑frontend architecture and module federation
• Strong experience building performant React applications using hooks and state management libraries such as Redux
• Experience with cloud‑native application development using Docker and containerized environments
• 1+ year hands‑on experience integrating LLM APIs (OpenAI, Anthropic, or equivalent) into production or near‑production systems
• Strong knowledge of JavaScript build tools such as Webpack and modern bundlers
• Proficiency with Chrome DevTools and frontend performance profiling tools
• Experience creating AI agents that use tool‑calling, function execution, and structured output
• Strong experience with data structures, algorithms, and database design
• Proven experience in software architecture, design patterns, and engineering best practices
• Experience with AWS cloud environments
• Experience with ecommerce/retail systems

Nice to Have

• Experience with public cloud services (Azure and GCP)
• Experience with legacy applications migration to modern stack
• Contributions to open‑source AI tooling or MCP ecosystem

Soft Skills

• Strong problem‑solving and debugging skills
• Excellent communication and collaboration abilities
• Ability to work independently and take ownership of projects
• Leadership and mentorship mindset
• Attention to detail and commitment to high‑quality user experiences

Why you will love GTS

• Join a powerful tech workforce and help us change the world through technology
• Professional development opportunities with international customers
• Collaborative work environment
• Career path and mentorship programs that will lead to new levels
• Join Lean Tech and contribute to shaping the data landscape within a dynamic and growing organization. Your skills will be honed, and your contributions will play a vital role in our continued success

Lean Tech is an equal opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees.