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Work

A compact portfolio with actual product pressure behind it.

I prefer a selective archive: fewer entries, better judgment, stronger systems.

Fullstack AI SaaS · CTO

ImpulsoLead

2025 — Present

Multi-tenant B2B SaaS for Brazilian real-estate teams. End-to-end architecture (Next.js, tRPC, Prisma, PostgreSQL), a LangGraph + Claude agent layer across 11 task types, dual payment gateway (Stripe + InfinitePay), and full i18n + LGPD compliance.

LLM research library · Python

CRAFT

2026

Causal Rationale Attribution Faithfulness Test — empirically checks whether an LLM agent’s stated reasoning causally drove its decision via a randomized perturbation experiment with a placebo control. Zero runtime deps, mypy-clean, CI-ready CLI with a --fail-under gate.

Adversarial LLM harness · TypeScript

red-agent

2026

Stress-testing framework that injects YAML-defined attacks into tool-using agents and uses a Claude LLM-judge to classify compromise vs. safe refusal vs. detection. 3 victim models, 5 attack categories, 4 safety metrics, persisted via Prisma with a Next.js dashboard.

AI coding-agent orchestrator · Python

treeport

2026

Runs AI coding agents (Claude Code, Aider, GPT-4o, Gemini) inside isolated Docker containers backed by git worktrees, then fast-forward merges the results. asyncio + Pydantic v2 + Typer, 5 backends, 48 passing tests.

Multi-agent SIEM · Python

CADRE

2026

Tests whether LangGraph-orchestrated agents outperform a monolithic LLM on threat-detection accuracy and cost. Ingests CIC-IDS2017 and UNSW-NB15, streams events over Redis, and gates response actions behind a sandboxed tRPC human-approval UI.

ML pipeline · Python

cardioML

2026

Reproducible heart-disease classification benchmarking 5 classifiers with Optuna tuning, MLflow tracking, and SHAP explainability. Reaches 0.93 AUC-ROC with SMOTE applied correctly inside the training fold.

Backend system design · FastAPI

Inventory-API

2025

Enterprise inventory API with ACID-compliant stock transfers: deterministic row-locking, atomic decrements, and DB-trigger-enforced immutable audit logs. Clean Controller–Service–Repository architecture; full stack starts with one docker compose up.

Consumer product · TypeScript

AppleVault

2025

Instant iPhone resale valuation with a personal device vault. Next.js (App Router), Clerk auth, tRPC, Prisma, and Tailwind, with a real-time price formula gated behind authentication.

Scientific computing · C++

n-body

2026

High-performance N-body gravitational simulator for the solar system, built in C++20 with symplectic integrators and real NASA ephemeris data.

AI search infrastructure

ImpulsoSearch

2024 — Present

Search and discovery layer for sourcing high-intent opportunities from noisy, unstructured real-estate channels.

Personal library SaaS

YourAlexandria

2025

A tiered-subscription reading platform with EPUB and PDF rendering, annotation layers (quotes, bookmarks, notes), and per-user storage accounting. Built on Next.js 15, Drizzle ORM, Neon Postgres, Cloudflare R2, Clerk, and Stripe.

Built for signal

Strong products earn attention twice: once visually, then again through execution.

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Aveiro, Portugal

© 2026 Alex De Souza. Fullstack & AI Engineer.