Home · Marcos Nespolo

Featured projects

Side projects, front to back

Solo builds where I explore applied AI in real product contexts. Designed, coded, and shipped from start to finish.

Production

HarmonizAi

Wine recommender by food pairing · classical NLP, no LLMs

spaCy + rapidfuzz pipeline parses free-text queries
1,688 wines scored on 4 transparent components
101 dishes hand-curated from sommelier literature

PythonspaCyFastAPISQLiteNext.js

Live demo GitHub Case study

In progress

Lume

Exploring applied AI in clinical workflows

Concept exploring RAG for clinical context
Fully designed and prototyped
Solo build, full ownership

Next.jsClaude APIPostgrespgvector

Live demo Case study

Archived

Atlantis

Aquarium fish-compatibility recommender · UFPR graduation project

Curated fish-species database
Compatibility checks across tank conditions
Built during graduation at UFPR

ReactNode.jsPostgres

Live demo GitHub Case study

Archived

AVIAO · APPrendendo

Technical-school capstone (2013). Math web app that teaches by exercise, never by reveal.

Built at 16, inside the AVIAO research group at IFPR
No answer reveal. Only progressive hints and content snippets
Pivoted from native Android to multi-platform web mid-project

PHPMySQLJavaScriptHTML5CSS3

Case study

Archived

ACAT

First project ever. A step-by-step trigonometry solver in C# (2011).

Built at 14, self-taught C# for the GUI
1st place · Innovation · IFPR Science Fair
Triangle solver picks sines/cosines/right-triangle automatically

C#.NET FrameworkWindows Forms

Download .exe (Windows)Case study

Journey

A trajectory told in moments

The moments that shaped how I work.

Hover or tap a moment to read more.

Experience

Career timeline

Roles, companies, and how the stack evolved.

Troquecommerce

Frontend Developer → Full Stack Developer → Product Engineer

2021–presentCurrent

~5 years

B2B SaaS for e-commerce exchanges and returns, with nearly 2,000 active stores. Monthly exchange and return volume grew 38% between September 2025 and September 2026.

Product EngineerJul 2025 – present

Built the platform's MCP server: stores connect their own AI chat, and shoppers open an exchange or return, get a shipping quote and track it within the conversation. Designed the tools and the instructions the AI follows, and refined them from real conversations.
Built the team's internal MCP server, with OAuth login and a knowledge base generated from the codebase on every build (per-store rules, 74 settings and 40+ platforms), answering in business terms what used to require code searches or Notion tables.
Standardized Claude Code across the team: versioned rules, 16 skills, 3 agents and guardrails such as blocking database writes through MCP.
Fixed the timeouts in the returns list and the main dashboard reports for the highest-volume stores (tables with tens of millions of rows) with database-side pagination and daily pre-aggregated tables: the list now loads in up to 1.4 s, and reports that used to exceed the 15 s limit load in under 0.5 s.
Built paid pickup: when free pickup is not available, shoppers pay for home pickup via Pix (Pagar.me). 87% of charges were paid, and the feature was released to all stores in October 2026.
Migrated the Shopify integration, used by about 400 stores a month, to GraphQL (exchange orders, inventory, coupons, gift cards and refunds), and extended the Salesforce Commerce Cloud integration.

Full Stack DeveloperOct 2022 – Jul 2025

Made the shopper returns portal multilingual (Portuguese, English and Spanish), with AI translation (OpenAI) of the exchange reasons each store configures, and created the international version of the platform.
Created the monorepo (Turborepo, Next.js and Supabase) that now hosts the company's applications.
Built the webhooks that notify stores of every exchange or return event, now active in more than 200 stores.
Extended the public API (more than 700 stores with an active token), with Swagger documentation and multiple tokens per store.
Developed the sign-up and statement screens for the digital account (Asaas) that stores use to refund shoppers.
Built the NPS survey in the returns portal and in emails, with a results dashboard: more than 3.2 million responses since 2023.

Frontend DeveloperJun 2021 – Oct 2022 · part-time

With the company since it was founded: helped prototype the platform's screens in Figma and create its visual identity, and built the front end with React, Next.js and TypeScript.

TypeScriptReactNext.jsNode.jsPostgreSQLSupabaseGraphQLOpenAI APIMCP

Nelogica

Frontend Developer · Home Broker team (crypto)

Feb – Sep 2022

8 months

Helped build the company's new product for the cryptocurrency market, on the Home Broker team
Kept latency low and the UI responsive in a system with thousands of concurrent users
Weekly releases, working directly with the UI/UX team

JavaScriptVue.jsSCSSHTML5

LinkYou Software & Integração

Software Developer

Mar – Jun 2021

4 months · freelance

Built Python integrations between online store, ERP and carrier APIs
Designed and proposed the company's new visual identity

PythonREST APIsDesign

Brazilian Army

Sergeant · IT Section deputy (2018–2021)

2016–2021

6 years

Deployed virtualized servers, administered Linux systems and set up backup routines
Built two internal systems for the base, in Django and in PHP with MySQL
From 2016 to 2018, administrative duties and instructor in training courses: around 720 soldiers and 110 corporals

LinuxDjangoPHPMySQLVirtualization

IFPR · CNPq Junior Research Fellow

Researcher and web developer · A.V.I.A.O.

2012–2013

1 year

Researcher and developer on A.V.I.A.O., an intelligent virtual environment for teaching math that identifies gaps in each student's learning and suggests study material
Built dynamic web pages with JavaScript, jQuery, HTML5, CSS3, PHP and SQL
Studied how interface ergonomics affects software acceptance

JavaScriptjQueryPHPSQLHTML5CSS3

Volunteer work

Outside the keyboard

Mar – Dec 2025

Rotaract

Treasurer

Invited to join the club while it was being formed and became its first treasurer. Besides the finances, helped plan the social projects and took part in trainings with other Rotaract and Rotary clubs. The day I remember most is Natal da Esperança, a Christmas we organized for the children of a local community: I was Santa Claus.

Apr – Nov 2023

WWOOF New Zealand

Wwoofer

In Wellington, volunteered in the vegan kitchen of a Hare Krishna community and built a system for devotees to book the temple's cars. In Little River, near Christchurch, helped a family remove and install a solar power system, did carpentry work, and learned GraphQL and ChatGPT integration from my host, a developer working in AI.

Feb 2020

ACRIDAS

Volunteer · Água no Sinal

Handed out cups of water at traffic lights in Curitiba in exchange for donations for at-risk children cared for by ACRIDAS (Christian Association of Social Assistance).

Apr 2016

TETO (TECHO)

Volunteer · Coleta

Took part in Coleta, the volunteer fundraising drive that funds TETO's housing projects throughout the year.

Education

Academic background

Five programs across federal universities and military training.

Universidade Federal do Paraná (UFPR)

Postgraduate · Applied Artificial Intelligence

2024–2025A · 90/100

Data architecture, machine learning, deep learning, big data and AI ethics
Computer vision, large-scale data analysis and end-to-end machine learning projects with Python, R and TensorFlow

Universidade Federal do Paraná (UFPR)

Postgraduate · Agile Software Development

2024–2025A · 94/100

Agile methods, software modeling and architecture, project management, DevOps and automated testing
Web and mobile projects with a focus on UX, plus automation and continuous deployment pipelines

Universidade Federal do Paraná (UFPR)

Associate Degree · Systems Analysis and Development

2018–2023

Final project: Atlantis, a web system built with React, Node.js and Supabase (Postgres)
Scrum and Kanban, React Native, NoSQL databases, IT governance, Java, PHP and C

Brazilian Army Sergeant School

Sergeant Technician · Ordnance (Metallurgy)

2014–2015

Technical training in metallurgy and in the maintenance, inspection and manufacturing of weapon components
Military logistics and leadership

Instituto Federal do Paraná (IFPR)

Technician · Computer Science / Software Development

2011–2013

Databases, programming (C, Java, PHP, HTML, CSS and OOP), UML and systems modeling
Built ACAT in C#: Innovation award at the 1st IFPR Science Fair
Helped set up a Samba server in the Database Lab as a shared repository for students

Skills

Day-to-day stack

Tools and frameworks I reach for.

AI / LLMs

MCPLLMsClaude CodeClaude APIOpenAI APIVercel AI SDKRAGpgvectorspaCyZod

Frontend

TypeScriptReactNext.jsTailwind CSSshadcn/uiMotion

Backend

Node.jsPostgreSQLSupabaseGraphQLREST APIsPythonFastAPI

Cloud / DevOps

VercelDockerGitHub ActionsLinux

Tools

GitGitHubTurborepoFigmaLinearCursor