Portfolio - Marcos Fitzsimons

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Works

Selected projects.

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Brixa

Live

2025 - PresentClient Work

Brixa

AI hotel operations platform automating guest communication and booking workflows, helping increase conversions while reducing repetitive work.

OpenAI API

React.js

Node.js

PostgreSQL

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2023 - 2024Client Work

Travel Booking App

Booking flow and admin surface for a tourism business, built to keep trips, content, and customer details manageable.

MongoDB

Express.js

React.js

Node.js

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Grab & Eat

Live

2024 - 2025Client Work

Grab & Eat

Autonomous grocery checkout: scan, purchase, leave without turning the store into a queue.

React Native

React.js

Node.js

PostgreSQL

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Claimence

Live

2025 - 2026Client Work

Claimence

Coverage analysis for financial-lines claims, narrowing policy noise into decisions people can act on.

AWS

Terraform

React.js

Node.js

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KeySwap

Live

2024Client Work

KeySwap

A piano practice tool for symmetric inversion, shaped for sessions where speed and clarity matter.

React.js

Node.js

PostgreSQL

TypeScript

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More Works

Skills

AI Product Systems

AgentsTool callingStructured outputsPrompt designContext engineeringEvaluationsGuardrailsHuman-in-the-loopLifecycle hooksOpenAI APIClaude APILangChainVercel AI SDK

Full-Stack Development

TypeScriptJavaScriptReact.jsNext.jsNode.jsExpress.jsREST APIsPostgreSQLMongoDBPrismaTypeORM

Mobile Development

React NativeCross-platform appsMobile product flows

Cloud & Infrastructure

AWSTerraformDockerDigitalOceanCI/CDDeployment workflows