Now · Building at a stealth AI startup · San Francisco · remote

I build AI agentsthat do real work.

I’m Felipe. I build production AI end to end: the LLM orchestration, the product around it and the guardrails that keep it safe. Right now I’m a founding engineer on Milo, where every employee gets an agent in its own microVM. Before that, agents that renegotiate debt at NG.CASH, and on the side MedAlvo, a prep company that runs itself. I like systems where a wrong answer costs real money, so I build them to fail loud, not silent.

See how they work Get in touch
Illustrated portrait of Felipe Ribeiro wearing an ITA varsity jacket
Felipe RibeiroAI engineer · ITA ’27
2017–20Olympiads · 50+ medals
2019Iniciativa Feynman
2023ITA · XP · BTG
2025Safra · LinkedIn · Credix
2026NG.CASH · MedAlvo
nowFounding engineer
Fig. 1: Trajectory, not to scaleStill climbing ↗
1stoverall, top goldIberoamerican Physics Olympiad 2020
50+olympiad medalsTwo international, 2017–2020
1 of 5ITA students pickedFor Future Lab, Telles Foundation’s first edition, 2026
Bestsatellite concept designMatsumoto-2, II SPOCS at ITA, 2026
01Inside the systems

How the things I build actually work

Results are the output. This is everything in between: how messages, models and deterministic code move through what I build. Real architecture, illustrative runs.

SlackMicrosoft TeamsGoogle ChatWhatsAppcodeGatewayact-as-user OAuth · streamingmodelAna’s agenther microVMmodelBruno’s agenthis microVMmodelCarla’s agenther microVMdataCompany brainpermissioned memorycodeHosted browserlive modedataCredential vaultOTPs & cards by aliasqualityEvals & autopsyship-gates · nightly LLM judge
personCustomerWhatsAppmodelWhispervoice → textcodeInjection guardtested on 34 attacksmodelPlannerGemini · picks the movecodePricing enginedeterministic codedataDeal stateDynamoDB · S3modelJudgeGemini · reviews
dataOfficial exams2,045 PDFsmodelScraper agentscloud VMscodeOCR + parsingtext, images, keyscodeDeduppgvector similaritymodelQA agentchecks answer keysdataQuestion bank163k+ questionscodeIRT 2PLdifficultycodeKnowledge tracingwhat you knowcodeFSRS v6when to reviewmodelThompson samplingpicks the next onepersonStudentweb & app
02Selected work

Things I’ve built

A company that makes money, a startup that got as far as a YC interview, open-source tools people install, and what I’m hacking on now.

Founder2026 —

MedAlvo

An adaptive prep platform for Brazilian medical residency exams, run as a self-driving company: AI agents in cloud VMs scrape, OCR, deduplicate and QA the question bank and handle daily operations. It makes money.

  • FSRS v6 + Thompson Sampling decide what each student sees next
  • 2PL IRT calibrates difficulty; Bayesian Knowledge Tracing models what you know
  • FastAPI + Postgres/pgvector on Cloud Run, React on the front
163k+official exam questions
2,045full past exams
  • FastAPI
  • Postgres
  • pgvector
  • Cloud Run
  • React
  • AI agents
medalvo.com.br
Open source2026

penpad

Turns Markdown + LaTeX notes into realistic handwritten pages for iPad, Goodnotes and reMarkable. A writer model varies every glyph while a legibility clamp keeps it readable. Watch it write.

  • Fractions, integrals, roots and vectors laid out in handwriting
  • Seed-reproducible output, offline, pure pip install, cross-OS CI
  • Python
  • resvg
  • LaTeX
Project page GitHub
A page of damped-oscillator physics notes rendered in handwriting by penpad
Side project2026

Curo

A WhatsApp-first patient-care layer for Brazilian specialists and clinics: one conversation for the patient, while Curo talks to the doctor, the hospital and the insurer. Built with my brother Rafael (MIT). We took it seriously for a while, far enough to interview with Y Combinator.

  • Agent with 14 tools for intake, scheduling, FAQ, documents and team handoff
  • Deterministic scheduling with idempotent bookings; per-clinic isolation from tenant one
  • Google ADK + Gemini on GCP, Postgres, clinic portal in React
  • Google ADK
  • Gemini
  • Postgres
  • React
  • WhatsApp
felipefrf.com/curo
Side project2026

Flight Price Finder

Finds the cheapest way between two cities, including hidden-city fares: a ticket to somewhere further that connects where you actually want to land. Every search proves it searched, because most of them find nothing, and that’s fine.

  • Real find: SSA→CGH direct was R$381; SSA→CGH→FLN was R$248
  • Groups nearby airports (GRU/CGH/VCP) and multi-leg through-fares
  • Fares come from Google Flights through treg; runs on my machine behind a Cloudflare Tunnel + Access
  • Python
  • treg
  • Google Flights
  • Cloudflare Tunnel

Live Google Flights data through treg

Hidden-city fare: get off at the connectionSSACGHFLNSalvadorSão Paulo · get off herenever flownDirect · R$381SSA→CGH→FLN · R$248−R$133
Side business2026

Ápice

A software house my brother and I run on the side. Two engineers, ITA and MIT: we design the system and write the code ourselves, for companies that need software that holds up.

See Ápice
  • Império Eventos

    Império Logística

    A logistics control tower (Next.js) and a field app for iOS and Android (Expo) on Supabase, reading stock from EstoqueNOW so the warehouse and the event crews see the same truth.

  • Clinics & specialists

    Patient-care agents

    WhatsApp agents for medical clinics that handle intake, scheduling and follow-ups.

Everything else on GitHub ↗
03Journey

Flight log

Remote roles across San Francisco, São Paulo, Belgium and New York, a few banks before that, and the things I built and led along the way.

Sep 2026 — now

Stealth AI startupFounding Engineer

Building Milo, a peer-to-peer personal AI for teams. Each employee’s agent runs in its own Linux microVM with their tools.

  • Shipped Microsoft Teams and Google Chat integrations at parity with Slack and WhatsApp: act-as-user OAuth, streaming, files and voice transcription.
  • Built the credential layer for the hosted browser agent: an encrypted vault where OTPs and secrets are injected by alias, so they never enter model context.
  • Eval-first shipping: bilingual ship-gate suites replaying production cases, nightly LLM-judged reviews, and an “autopsy” tool that reconstructs any conversation end to end.
San Francisco · remote
Jan 2026 — Sep 2026

NG.CASHProduct Engineer

Production LLM agents and full-stack systems for a Brazilian fintech, where a wrong answer costs real money.

  • WhatsApp debt-negotiation agent with multi-model orchestration and pricing kept deterministic in code: 19% lower latency, 0 leaks across a 34-attack prompt-injection battery.
  • Re-platformed legacy payroll into Fastify + React on Cloud Run with Terraform, plus a Gemini pipeline that validates contractor invoices.
  • Automated Legal’s judicial-notification triage with multimodal OCR and entity extraction, removing ~95% of manual review.
São Paulo · remote
Jul 2025 — Jan 2026

CredixML Engineer, Credit & Risk

Credit models for emerging-market B2B buyers that became the automated decision engine and drove seller pricing.

  • XGBoost and logistic-regression classifiers that bucket buyers by predicted DPD and loss, deployed to production.
  • SQL + Python pipelines for near-real-time decisioning, with anomaly detection flagging fraud.
Belgium · remote
Feb 2025 — Jul 2025

LinkedInSales Strategy Intern, Data & AI

Worked with the US & Canada sales team from Brazil.

  • Shipped an LLM chatbot over Salesforce CRM data that replaced analyst-mediated revenue forecasts.
New York · remote

Earlier: internships & research

  • Jan — Feb 2025Safra US Equities Summer InternNLP pipeline over SEC EDGAR 10-Ks
  • Apr — Aug 2024BTG Pactual Automation Engineer InternAutomations for Legal and the reforestation business; a stint as PM
  • Dec 2023 — Feb 2024XP Inc. Product Control Summer InternSpreadsheet automation for product control
  • Aug 2023 — Apr 2024CNPq Undergraduate research, MLMLPs vs CNNs on MNIST, 97.4% → 99.2% accuracy

Building & leading

  • 2023 — 2024ITA Jobs Commission PresidentRan Brazil’s largest countryside career fair, 1,800+ attendees
  • Mar — Oct 2024Fundação Estudar MultiplicadorWorkshops and mentoring for students from underrepresented backgrounds
  • Sep 2019 — Apr 2021Iniciativa Feynman Co-founder & Coordinator0 → 81 volunteers in under 6 months, 350+ public-school students during COVID
04Olympiads & honors

Before all this

From 2017 to 2020 I trained for physics, math and robotics olympiads. It’s where I learned to like problems that don’t have a known answer yet.

OLIMPÍADA IBEROAMERICANA DE FÍSICA · 2020 · 1stTOP GOLD
International · 2020Top gold, 1st place overallIberoamerican Physics Olympiad (OIbF)1st overall, plus the special prize for the best solution to Problem 2.
NORDIC-BALTIC PHYSICS OLYMPIAD · 2020 · AgSILVER
International · 2020Silver medalNordic-Baltic Physics Olympiad (NBPhO)Special prize for the best solution to Problem 1. 21.4 of 36.5 points, 16th overall, in Brazil’s first year as a guest.
National · 2017–202050+national olympiad medals
  • OBF 4× gold
  • OBA 2× gold
  • OBR 2× gold, silver
  • OBMEP Gold
Certificate of the Olimpiada Iberoamericana de Física virtual 2020 issued to Felipe Farias Ribeiro Filho, representing Brazil
OIbF virtual 2020 certificate, 5–13 December 2020SBF announcement ↗
Olimpiada Iberoamericana de Física 2020MEDALLERO
NombreApellidoPaísMedallaPremio especial
FelipeFarias Ribeiro FilhoBrasilOROMejor resolución del problema 2
Row 1 of the official OIbF 2020 medal table (46 awardees)Official medal table ↗
NBPhO 2020 final results21.4 / 36.5 pts · #16
  • P16/6
  • P22/10
  • P33/3
  • P45.2/9
  • P55.2/8.5
Silver, 16th overallOfficial results ↗

Recent recognition

Four of the Matsumoto-2 team holding “Melhor Trabalho de Graduação” certificates next to the satellite poster at ITA
Best satellite conceptMatsumoto-2 · II SPOCS, ITA · July 2026A C-band SAR satellite to map farmland in Rio Grande do Norte, designed by a team of six. Best graduation project at ITA’s satellite concept design seminar.
Felipe listening during a Future Lab session in São Paulo
Future Lab 2026Telles Foundation · July–August 2026One of five ITA students selected for the first edition, a six-week program for up to 50 people, all by nomination.
Felipe and three friends at the Brasil Project conference in Cambridge
Brasil ProjectHarvard & MIT · Cambridge, 2026Invited to the conference where Brazilians at the frontier of research and industry discuss the country’s future.
The SkyLens team on stage at the Nameless Hackathon, under a screen that reads “2º lugar · SkyLens”
2nd placeSkyLens · Nameless Hackathon (VC-backed), 2025CBERS-4A satellite imagery from INPE, pansharpened to 2 m mosaics, to find urban growth in rural-taxed land.
Education · Feb 2023 — Dec 2027

Instituto Tecnológico de Aeronáutica (ITA)

Aerospace Engineering, Data Science minor. Run by the Brazilian Air Force since 1950 and widely regarded as the best engineering school in Brazil.

24thplace in the entrance exam
4,033open-track applicants
144seats
05How I work

AI-native, by default

Most of my code is written with a fleet of agents: Claude Code and Codex running in parallel git worktrees, on a remote box, inside tmux. I spend my time on specs, review and evals.

I ship eval-first. If a change touches a model, it doesn’t merge until it passes suites built from real production cases. Anything that has to be exact, like prices, money and credentials, stays in deterministic code and out of the model’s hands.

~ tmux attach -t fleet
  agent-1  feat/streaming     ✓ evals passing
  agent-2  fix/retry-backoff  ✓ evals passing
  agent-3  chore/qa-batch     running…

Illustrative. The agent box sits behind a Cloudflare tunnel on this same domain.

AI & agents
  • LLM agents
  • Multi-agent orchestration
  • Tool use & MCP
  • RAG
  • Evals & guardrails
  • PyTorch
Product
  • TypeScript
  • Node
  • Next.js
  • React
  • Fastify
  • FastAPI
  • Python
Data
  • Postgres
  • pgvector
  • Snowflake
  • DynamoDB
  • XGBoost
  • SQL
Infra
  • GCP Cloud Run
  • AWS
  • Terraform
  • Docker
  • GitHub Actions
  • Linux

Let’s build something
that holds up.

felipe.frf27@gmail.com LinkedInGitHub