SmartPenny
Personal-finance web app: a unified dashboard for spending and investments, smart invoice/receipt parsing with automatic categorization (DQA), and budget management with real-time tracking.
Private project
Lisbon, Portugal
Hi there, I'm
João Caldeira
a
Mostly I build things, break things, and automate the boring parts, and somewhere in there I fell for trading systems.
Published in Computational Economics (Springer)01 / About
A bit about me
Lately I'm just as focused on how I build as what I build, squeezing the most out of coding agents and new AI tooling to make my day-to-day workflow faster and sharper.
Financial markets have a particular grip on me: my MSc thesis dug into ML models for predicting market trends, and I've been hooked on trading systems ever since.
Away from the keyboard, I'm usually reading about space exploration, putting in work at the gym, or three tabs deep in the latest AI news.
Based in Lisbon · MSc in Computer Science & Engineering
02 / Experience
Where I've worked & studied
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Software Engineer Infosistema -
QA Automation Engineer Sky - QA Automation Apprentice Sky
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MSc · CS&E Instituto Superior Técnico - BSc · CS&E Instituto Superior Técnico
Work
Education
Software Engineer Work
Infosistema- Building an AI-powered B2B SaaS platform end-to-end, designing document-understanding systems that extract structured data from unstructured documents and remove hours of manual work.
- Engineering agentic AI pipelines (LLMs, RAG, MCP, Google ADK) and the data integrations behind them, connecting cloud-storage sources with secure, permission-scoped access.
- Owning the full lifecycle across a microservices architecture, from backend APIs to frontend dashboards, deployed on GCP with automated CI/CD and built to enterprise security standards.
QA Automation Engineer Work
Sky- Built an API telemetry framework to monitor critical user journeys, improving performance visibility and reducing service defects.
- Optimized CI/CD pipelines by integrating automated reporting into communication channels, streamlining workflows and boosting client adoption.
- Led a restructuring of the automation test suite, improving quality, scope and relevance for client teams.
Apprentice QA Automation Work
Sky- Developed automated frameworks for resilience testing across mobile, TV and web platforms.
- Gained hands-on experience with Selenium, Appium, Playwright and Cypress.
MSc in Computer Science & Engineering Education
Instituto Superior Técnico- Specialization in Enterprise Systems and Service Management.
- Master's thesis: Dynamic Ensemble of Specialized Models for Multi-Timeframe Stock Market Trend Prediction.
BSc in Computer Science & Engineering Education
Instituto Superior Técnico- Strong foundation in algorithms, data structures, AI, operating systems and computer networks.
- Mentored first-year students with academic guidance and campus resources.
03 / Projects
Things I've built
Portfolio v2
This very website, built with Astro: full-screen scroll-snap sections, an interactive particle backdrop and a tabbed experience timeline.
Ricochet Robots Solver
Solves the Ricochet Robots puzzle in the fewest moves by formulating it as a tree-search problem and traversing it with the RBFS (Recursive Best-First Search) algorithm.
Slopwatch
Tracks AI-slop indicators (CLAUDE.md, .cursor, AGENTS.md) across open-source GitHub repos. Built a ~280k-repo dataset with full metadata, an enrichment pipeline and ongoing snapshot refresh.
Private / archived
Portfolio v1
My first portfolio: a single-page scrolling site built from scratch with vanilla HTML, CSS and JavaScript. Where I first explored front-end design.
Vertex Capacity Graph
Implements Dinic's algorithm to compute maximum flow in a quadrangular graph with vertex capacities and super-sources, solving a conceptual optimization problem.
MST with Union-Find
Maximum connectivity at minimum cost for a transportation network: Kruskal's algorithm finding the minimum spanning tree using a Union-Find (by rank) data structure.
Circular String Linearization
Finds the smallest lexicographic cyclic rotation of a string in linear time by building a Suffix Tree with Ukkonen's algorithm.
04 / Contact
Let's build something
Got a project, an opportunity, or just want to say hi? My inbox is always open.