Software Engineer · Belo Horizonte, Brazil

Diogo Martins de Assis.

I build payment systems, Open Finance integrations and AI-powered products — currently moving money for millions of users at Serasa.

510k+transactions / month
1M+Open Finance consents
2,000+companies on AI agent

01Experience

Software Engineer II

Serasa · Payments team

Jun 2026 — Present · Remote

  • Built Open Finance data requests (investments, credit, FX) on a platform with 1M+ organic consents, adding 10 new data types.
  • Work on Pix, bank slip and transfer flows handling 510k+ transactions/month — 78% of Limpa Nome deals use Pix.
  • Improved idempotency of SQS/SNS payment events with Redis, cutting duplicate payment incidents by 40%.
  • Open Finance payment initiation so users pay debts from other banks without leaving the app.
  • Improved Datadog monitoring for Pix and bank slip flows, cutting incident detection to under 10 minutes.

C# · .NET · AWS · Kubernetes · Redis · GitLab CI/CD · Datadog · Databricks

Software Engineer

Fiscal.io · Core team

May 2023 — Jan 2026 · Belo Horizonte

  • Key contributor to migrating a .NET WinForms desktop app to Angular + .NET Core, moving 60%+ of active users to the web in 18 months.
  • Core contributor to an AI fiscal agent — an MCP server (MCP C# SDK) that lets Claude, ChatGPT and Cursor query fiscal data. Adopted by 2,000+ companies in 6 months.
  • Co-built LLM invoice classification (CFOP, CST, NCM) with Semantic Kernel and OpenAI, reaching 92% accuracy.
  • Co-developed the SEFAZ × ERP × SPED reconciliation engine, cutting reconciliation from days to under 2 hours.
  • Contributed to the RabbitMQ/AWS pipeline capturing 270M+ documents/month, cutting latency by 35%.

MCP C# SDK · Semantic Kernel · OpenAI & Anthropic SDKs · RAG · C# · Angular · TypeScript · RabbitMQ · AWS · SQL Server

02Projects

Empenhando

SaaS tracking government purchase commitments and payments for public suppliers. Rate-limited Portal da Transparência gateway (DynamoDB lease, sliding windows, backoff, DLQ) with caching that caps CNPJ lookups at 2 calls.

Go · React · TypeScript · DynamoDB · SQS · Stripe

empenhando.com.br ↗

Algorithms in Sight

Educational platform helping developers learn algorithms, data structures and system design through accessible study resources.

HTML · Render · GoatCounter

algoritmos-a-vista.onrender.com ↗

03Research

Undergraduate researcher at the Computer Science Department (DCC) of UFMG — Federal University of Minas Gerais — across two research projects, bridging machine learning with human perception and large-scale text classification.

Eye-Tracking and Neuro-Affective Architecture (e.MANA)

  • Trained machine learning models on biometric eye-tracking data from subjects viewing architectural images, supporting a PhD thesis on neuro-affective architectural modeling that connects neuroscience and affective computing with parametric design.
  • Contributed to the manuscript derived from the thesis, being prepared for submission to Frontiers of Architectural Research.

Machine Learning · Affective Computing · Neuroarchitecture · Python

Instance Selection for Extreme Multi-Label Text Classification

  • Investigating how instance selection (removing redundant and noisy training data) affects the efficiency and effectiveness of a retrieval-and-fusion system (RAG-Fuse) for extreme multi-label text classification (XMTC), with emphasis on rare ("tail") label performance.

Information Retrieval · RAG · XMTC

Explainability and Statistical Rigor

  • Analyzing why model effectiveness often survives aggressive data reduction, using rigorous statistical testing to tell genuine data redundancy apart from insufficient statistical power.

Statistical Analysis · Python

04Skills

Languages

  • C#
  • Go
  • TypeScript
  • JavaScript
  • Python
  • Java
  • HTML
  • CSS

Frameworks & AI

  • .NET
  • ASP.NET Core
  • Angular
  • React
  • Next.js
  • RabbitMQ
  • MCP SDK
  • Semantic Kernel
  • RAG
  • Claude
  • Cursor
  • OpenAI SDK
  • Anthropic SDK

Databases

  • PostgreSQL
  • SQL Server
  • MySQL
  • Oracle
  • Redis
  • DynamoDB

Infrastructure & Analytics

  • AWS
  • Kubernetes
  • Docker
  • GitHub Actions
  • GitLab CI/CD
  • Datadog
  • Databricks

05Education

Bachelor of Engineering in Software Engineering

PUC Minas — Pontifical Catholic University of Minas Gerais

2022 — 2025

Let's build something.

Open to interesting engineering problems — whatever the domain.