Software engineering · Rio de Janeiro, Brazil — remote
Patrick
Arinelli
Patrick Arinelli is a senior software engineer and systems architect with 9+ years of experience, specialized in Brazilian payments infrastructure — Pix, boleto, and direct integrations with Banco do Brasil and Santander — and AI-orchestrated systems with LangGraph. Founder of Cérebro Amigo. Builds business-critical systems in .NET, Go, TypeScript, and Python for fintechs and SaaS companies.
Who is Patrick Arinelli?
Patrick Arinelli is a Brazilian software engineer based in Rio de Janeiro, with more than nine years of experience in backend, full stack, and systems architecture. He was the first developer at Fradema Consultores Tributários, where he built the company’s technology foundation from the ground up: five CRMs, a ticketing application, microservices, automation tools, AI-powered workflows, and banking integrations serving more than 6,000 clients.
He now works as an independent contractor on payments, fintech, and SaaS projects, and is the founder of Cérebro Amigo, an AI mental health platform. Away from the terminal, he is an independent musician with releases distributed by Nagant Records.
What does Patrick Arinelli specialize in?
Brazilian payments
End-to-end Pix — EMV BR Code, static and dynamic QR codes, confirmation webhooks — registered boleto payments, receivables reconciliation, and billing workflows. Direct integrations with Banco do Brasil and Santander APIs, without an intermediary PSP: hands-on bank integration experience reveals where statements can mislead.
AI-orchestrated systems
Production agents with LangGraph and LangSmith, RAG over PostgreSQL/pgvector, and human-in-the-loop pipelines. Architectural principle: the LLM gets the phone, never the pen — no irreversible business action happens without deterministic validation outside the model.
Core stack
Projects
AI mental health platform: structured clinical screening, follow-up agents, and an LGPD/CFM compliance layer built in from the first commit.
Autonomous collections agent
A debt negotiation agent — beyond scheduled payment reminders — with safety invariants: no agreement is finalized without deterministic validation of the proposal’s permitted terms. Go on the critical path, LangGraph for orchestration.
doc-extract
A .NET library for deterministic parsing of Brazilian financial documents: boleto payment lines and barcodes, NF-e access keys, and Pix EMV BR Code, with an OCR fallback.
Experience
Independent contractor · Senior engineer & architect
Payments, fintech, SaaS, and AI systems for clients in Brazil and abroad. Working remotely in English and Portuguese.
Fradema Consultores Tributários · First developer
Built the company’s technology foundation from scratch: five CRMs, ticketing, microservices, automation, AI-powered workflows, and banking integrations (Banco do Brasil and Santander) serving more than 6,000 clients.
Away from the terminal
Patrick Arinelli is also an independent musician, with releases distributed by Nagant Records. High-gain guitar, self-produced music — the same obsession with a clean signal, applied to a different kind of pipeline.
Frequently asked questions
Is Patrick Arinelli available for new contracts?
Yes. Patrick Arinelli takes on remote contracts as a senior software engineer and architect, focusing on payments, fintech, SaaS, and AI systems. Get in touch by email or LinkedIn.
What are Patrick Arinelli’s specialties?
Brazilian payments infrastructure — Pix (EMV BR Code, dynamic QR codes, webhooks), registered boleto payments, and direct integrations with Banco do Brasil and Santander APIs, without an intermediary PSP — and production AI-orchestrated systems with LangGraph, LangSmith, and RAG over PostgreSQL/pgvector.
Which technologies does Patrick Arinelli work with?
.NET/C#, Golang, TypeScript/Node.js (NestJS, Next.js), Python (FastAPI), Scala, and Kotlin; PostgreSQL and SQL Server; Azure and AWS; Docker, Kubernetes, and GitHub Actions; LangGraph and LangSmith; observability with Datadog, Sentry, Grafana, and Prometheus.
What is Cérebro Amigo?
Cérebro Amigo is an AI mental health platform founded by Patrick Arinelli, with structured clinical screening and an LGPD/CFM compliance layer. Visit cerebroamigo.com.br.
How can I hire Patrick Arinelli?
Email contato@patrickarinelli.com or reach out on LinkedIn. Remote work from Rio de Janeiro, in English or Portuguese.