Carlos.
Open to new opportunities

Hi, I'm Carlos Monsalve

Senior Full Stack
Engineer.

I build scalable web applications and modern digital experiences using TypeScript, Next.js, NestJS and AI-powered technologies.

View my workMy experience↓ Download CV
Full StackEngineering
TypeScriptPrimary language
AIAssisted Development

About me

Building scalable software with a product mindset.

I enjoy transforming complex requirements into reliable, maintainable and high-quality software.

Senior Full Stack Engineer specialized in building scalable web applications with TypeScript. I have experience designing and developing full-stack applications using Next.js, NestJS and Laravel, contributing across the entire software development lifecycle—from software architecture and backend services to frontend development and deployment.

Full Stack Development

Building modern web applications across frontend, backend and infrastructure.

Software Architecture

Applying Clean Architecture, Domain-Driven Design and scalable patterns.

AI-Assisted Development

Leveraging AI tools to improve software design, development and productivity.

Experience

Building software across the full stack.

My experience spans frontend development, backend architecture, APIs, cloud integrations and scalable web platforms.

2024 — 2026

Madrid, Spain

Senior Full Stack Engineer

Gelt · Full-time

Contributed to the design and development of scalable web platforms and backend services, working across the full software development lifecycle.

  • Designed and developed full-stack applications using TypeScript and Next.js.
  • Built backend services and REST APIs.
  • Applied Domain-Driven Design and Clean Architecture principles.
  • Worked with authentication, authorization and secure application flows.
  • Integrated external services and cloud platforms.
  • Collaborated with product and engineering teams to deliver business-driven solutions.
TypeScriptNext.jsReactLaravelPostgreSQLMySQLPrismaAWS

Selected Projects

Building products that solve real problems.

A selection of platforms and systems I have contributed to across frontend, backend and software architecture.

Web Platform

Administration Platform

Full Stack Web Application

A modern administration platform designed to manage business operations, users, promotions and application data through a centralized backoffice.

The challenge

Create a scalable and maintainable administration platform capable of supporting multiple business workflows while keeping the architecture clean and flexible.

My contribution

Designed and developed the full-stack application, contributing to frontend architecture, authentication flows, backend integrations and data management.

  • Full-stack development with Next.js and TypeScript.
  • Authentication and authorization flows.
  • Scalable application architecture.
  • Form validation and data management.
  • Cloud storage integration.
Next.jsTypeScriptReactPrismaMySQLNextAuthAWS S3Zod
Fintech

Cashback & Wallet Platform

Customer Rewards Platform

A digital platform focused on cashback, wallet management and customer rewards, providing users with a centralized experience for managing their benefits.

The challenge

Build a reliable platform capable of managing user authentication, transactions, balances and reward-related workflows.

My contribution

Contributed to the development of frontend and backend functionality, building user experiences, integrations and services that supported the platform.

  • Secure authentication flows.
  • Wallet and cashback functionality.
  • Real-time dashboards.
  • Multi-language support.
  • API integrations.
TypeScriptReactNext.jsREST APIsPostgreSQL
Backend

Multi-Tenant Loyalty Platform

Scalable Backend Architecture

A backend platform designed to support multiple tenants and loyalty programs, including wallets, rewards, cashouts and customer-related operations.

The challenge

Design backend services capable of supporting multiple tenants while maintaining separation of concerns and scalability.

My contribution

Worked on backend services and API architecture, applying modular design principles and building integrations for loyalty and rewards workflows.

  • Multi-tenant architecture.
  • Wallet and rewards management.
  • REST API design.
  • Scalable backend services.
  • Business domain modeling.
TypeScriptNode.jsREST APIsPostgreSQLMulti-tenancy

Engineering

How I approach software development.

Beyond writing code, I focus on architecture, maintainability, product needs and delivering reliable solutions.

Architecture

I design software with maintainability and scalability in mind, applying principles such as separation of concerns, Domain-Driven Design and Clean Architecture when they add real value.

Clean ArchitectureDomain-Driven DesignSOLID PrinciplesModular Design

Backend & APIs

I build backend services and APIs focused on clear contracts, maintainability, security and business-driven design.

REST APIsAuthenticationAuthorizationJWTOAuth2

Quality

I focus on writing readable, maintainable and reliable code, using validation, testing and code reviews as part of the development process.

Type SafetyValidationTestingCode Reviews

AI-Assisted Development

I leverage AI tools to accelerate development, explore solutions, improve code quality and support technical decision-making while keeping engineering judgment in control.

ChatGPTGitHub CopilotCursorLLM Integration

Tech Stack

Technologies I work with.

A selection of the technologies, tools and engineering practices I use to build modern software.

Frontend

Building modern and interactive user experiences.

TypeScriptJavaScriptReactNext.jsHTMLCSSTailwind CSSMaterial UI

Backend

Designing APIs and scalable backend services.

Node.jsNestJSLaravelPHPREST APIs

Data

Working with relational databases and modern ORMs.

PostgreSQLMySQLPrismaSQL

Cloud & Integrations

Connecting applications with cloud platforms and external services.

AWSAWS S3AWS SESSalesforceCloudflare

Engineering

Building maintainable and scalable software.

DDDClean ArchitectureSOLIDDesign PatternsJestZod

AI & Productivity

Using AI to accelerate development and build intelligent applications.

Google GeminiChatGPTGitHub CopilotCursorLLM Integration

Contact

Let's build something great together.

I'm open to new opportunities, interesting projects and conversations about technology.

Let's connect

Whether you're looking for a Senior Full Stack Engineer, want to discuss a project or simply connect, feel free to reach out.

Email

monsalvecarlos@gmail.com

LinkedIn

Connect professionally

GitHub

Explore my code