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Full-stack engineer · Frontend, backend and AI

Luis Otavio

I build web products end to end: polished React frontends, solid backends and APIs, and AI features where they earn their place.

frontendapidatabaseauthinfraaiproduct
  • 30,000+active subscribers on Tapnote, whose web app I built as sole developer
  • 3rd placein the Amazon Challenge with Terra Krya, R$ 100,000 in funding
  • 3+ yearsshipping production software, since Jan 2023
  • 124GitHub stars on my open-source WhatsApp assistant

01 / Selected work

Things I haveshipped.

Featured work first, each broken down into the problem, what I built, the stack and the outcome. Everything else lives in the archive below.

01Tapnote, Poland2026Sole developer

Tapnote Web

Problem

Poland's #1 AI tutor app, with 30,000+ active subscribers, lived on mobile. Students needed the same tutor on the web.

What I built

  • Architected the full-stack web app with Next.js, React, TypeScript, Tailwind CSS and Node.js, reaching feature parity with the native mobile app.
  • Engineered AI tutoring features with LLMs and RAG on a PostgreSQL / Supabase backend for context-aware homework help and personalized study assistance.
  • Next.js
  • React
  • TypeScript
  • Tailwind CSS
  • Node.js
  • PostgreSQL
  • Supabase
  • LLMs
  • RAG

Impact

30,000+

active subscribers on the app it extends

  • Feature parity with the native mobile app
  • Context-aware tutoring grounded with RAG
web.tapnote.app

02Akdo.ai, Germany2025–26Full-stack developer

Enterprise Training Platform

Problem

Companies needed a training platform where courses could be created automatically, with each organization's users and data strictly isolated.

What I built

  • Architected the platform in Next.js, integrating automated course creation with LLM-driven content generation.
  • Owned the end-to-end multi-organization authentication system with Better Auth for secure tenant isolation.
  • Designed and shipped a peer review system so training creators receive structured feedback and ratings.
  • Next.js
  • TypeScript
  • Better Auth
  • LLMs

Impact

Multi-tenant

auth with secure isolation per organization

  • Secure tenant isolation across organizations
  • Structured peer feedback and ratings for course creators
akdo.ai

03Terra Krya, Brazil2026Bot developer

Curupira

Problem

Volunteer fire brigades in central Brazil coordinate in group chats, far from the Caminho do Fogo platform where alerts, fires and field actions are recorded. I build the bot; Terra Krya brings it to the brigades.

What I built

  • WhatsApp and Telegram agent with one shared memory: brigade members sign in from the chat, then report alerts and fires with a location pin and photos, each write confirmed before it is saved.
  • Fire status updates, field actions, area notifications and the INPE fire-risk forecast up to three days ahead, all by conversation.
  • RAG over brigade documents with citations, plus voice notes in and out.
  • TypeScript
  • Fastify
  • Baileys
  • grammY
  • Python
  • FastAPI
  • Pydantic AI
  • Gemini
  • PostgreSQL
  • pgvector
  • Redis Streams
  • Docker

Impact

84 users

across 10 brigade groups of 30+ people

  • Field reports reach the platform straight from the group chat
  • Brigades are notified when a fire is registered in their area
caminhodofogo.com.br

04Terra Krya, Brazil2026Bot developer

OCA IÊ

Problem

Brazil-nut (castanha) collectors in northern Brazil sell with little visibility into what the harvest is fetching in other regions. I build the bot; Terra Krya brings it to the communities.

What I built

  • WhatsApp agent on the IE Sociobio platform: producers log prices just by talking, and compare their region with others.
  • A weekly regional recap posted to each group, with prices, harvest counters and phase, rewritten or rescheduled by asking the bot.
  • The Caderno da Safra harvest survey answered by conversation, plus operator broadcasts paced to stay clear of spam detection.
  • TypeScript
  • Fastify
  • Baileys
  • Python
  • FastAPI
  • Pydantic AI
  • Gemini
  • PostgreSQL
  • pgvector
  • Redis Streams
  • Docker

Impact

34 users

across 5 producer groups of 10+ people

  • Prices shared across regions every week, from the platform's own data
  • Harvest survey filled in without leaving WhatsApp
iesociobio.org

05Open source, WAppAIOSSAuthor

WhatsApp Chatbot Assistant

Problem

Bring context-aware LLM answers into the chat app people already use every day.

What I built

  • Open-source WhatsApp chatbot that connects LLMs, including Bing AI, to WhatsApp conversations.
  • TypeScript
  • Node.js
  • LangChain
  • Prisma
  • Docker

Impact

124 ★

GitHub stars and 38 forks

  • Most-starred repository on my profile
  • Forked 38 times by other developers
WAppAI/assistant

06LangChain.js, open source2024Contributor

Google Routes Tool

Problem

LangChain.js agents had no native way to plan routes, so travel and logistics agents had to hand-roll Google Maps calls.

What I built

  • Contributed the Google Routes Tool to LangChain.js: agents can ask for routes, travel times and distances through Google's Routes API.
  • Shipped with docs and tests, reviewed and merged by the LangChain maintainers.
  • TypeScript
  • LangChain.js
  • Google Routes API

Impact

Merged

into LangChain.js, May 2024

langchain-ai/langchainjs#5329

07Awana Digital, USA2024

Amazon Challenge with Terra Krya

Make environmental data reachable through conversation instead of raw datasets.

  • Engineered autonomous AI agents with LangChain, Smolagents and Mem0 that power conversational interfaces for environmental data.
  • Led the Amazon Challenge implementation with Terra Krya.

3rd place

Amazon Challenge, R$ 100,000 in funding

desafiopelaamazonia.com.br
  • LangChain
  • Smolagents
  • Mem0
  • Python

08Underdogs, Italy2024–25

Web Platform, CRM and Automation

Operations depended on third-party automation tools and hours of manual work every week.

  • Built the full-stack web platform with Next.js, React and Tailwind CSS.
  • Designed and shipped a custom CRM from scratch, removing the dependency on third-party automation tools.
  • Automated 20+ business workflows with Zapier, n8n and Make, plus an internal chatbot handling 100+ daily queries.

40+ h / week

of manual work saved across teams

  • Next.js
  • React
  • Tailwind CSS
  • Zapier
  • n8n
  • Make

Archive 34

All projects

02 / Experience

Where I haveworked.

Remote with teams in Poland, Germany, Italy and the US, after starting on-site at Huawei in Brazil.

  1. Feb 2026 – Jun 2026Poland · Remote

    Tapnote

    Full-stack Developer
    • Sole developer of the web counterpart to Poland's #1 AI tutor app, serving 30,000+ active subscribers.
    • Reached feature parity with the native app; built LLM and RAG tutoring on PostgreSQL / Supabase.
    • Next.js
    • TypeScript
    • Supabase
    • RAG
  2. Jul 2025 – Jan 2026Germany · Remote

    Akdo.ai

    Full-stack Developer
    • Architected an AI enterprise training platform with LLM-driven course generation.
    • Owned multi-organization auth with Better Auth and shipped a peer review system for course creators.
    • Next.js
    • Better Auth
    • LLMs
  3. Nov 2024 – Jul 2025Italy · Remote

    Underdogs

    Full-stack Developer & Automation Lead
    • Built the web platform and a custom CRM from scratch.
    • Automated 20+ workflows saving 40+ hours a week; shipped a chatbot handling 100+ daily queries.
    • Next.js
    • Zapier
    • n8n
    • Make
  4. Apr 2024 – Nov 2024USA · Remote

    Awana Digital

    AI Engineer
    • Engineered autonomous agents with LangChain, Smolagents and Mem0 for conversational access to environmental data.
    • Led the Amazon Challenge implementation with Terra Krya: 3rd place, R$ 100,000 in funding.
    • LangChain
    • Smolagents
    • Mem0
  • 2019 – 2023BS, Computer EngineeringSorocaba University of Engineering
  • 2024 – PresentBS, System DevelopmentPontifical Catholic University of Paraná

03 / GitHub

In the open.

@Luisotee on GitHub
public repositories
45
stars on WAppAI/assistant
124
forks of WAppAI/assistant
38
stars on earth-defenders-assistant
13

Achievements

  • Pair Extraordinaire×4
  • Pull Shark×3
  • Quickdraw
  • YOLO
  • Arctic Code Vault

Pinned languages

  • TypeScript 3
  • Python 2
  • JavaScript 1

04 / Contact

Have somethingto build?