Nahuel Santos

Software Engineer

location Barcelona, Catalonia, Spain
A pragmatic and experienced engineering leader with over 15 years designing, building, and scaling complex software systems. Proven ability to architect robust solutions (.NET, Go, Microservices, AWS), lead technical initiatives across teams, and drive significant improvements in performance, reliability, and developer productivity. Adept at translating ambiguous business needs into concrete technical strategies, mentoring engineers, and fostering collaboration. Excels at tackling large-scale integration challenges, modernizing legacy systems, and taking ownership from concept through production deployment.

Experience

Founder & CTO @ Staysy

Apr 2026 – Present

Barcelona, Spain

  • Founded Staysy, an app-free digital guidebook for short-term rental hosts: guests open a single link for check-in details, WiFi, house rules, local tips and emergency contacts, with nothing to install.
  • Own the product end to end as a solo founder: research, positioning, design, build, launch and iteration, from the first prototype to paying customers.
  • Run the commercial side: free and Pro plans, subscription billing, pricing and onboarding, plus the sales and support conversations that decide what gets built next.
  • Delivered the platform for hosts managing 10-20+ properties, with per-booking guest access that expires automatically at checkout and support for English, Spanish and French.
  • Also own delivery, security and operations: automated tests, staged releases before production, and documented, repeatable deploys on self-hosted infrastructure.

Senior Software Engineer @ AilyLabs

Oct 2023 – Present

Barcelona, Spain

  • Leading backend development for a multi-tenant AI analytics platform using .NET Core, designing and implementing scalable microservices and core features consumed via a Backend-for-Frontend (BFF) architecture.
  • Architecting solutions and providing technical guidance across multiple teams and senior engineers, ensuring consistency and quality.
  • Proactively identifying and addressing performance bottlenecks and architectural limitations in existing services, managing the modernization of legacy components.
  • Driving improvements in system observability using Datadog and Sentry within AWS.
  • Contributing to frontend development (React/React Native) and managing multi-tenancy aspects via Piranha CMS.

Senior Software Engineer @ Milestone Systems

Oct 2022 – Oct 2023

Barcelona, Spain

  • Designed and developed microservices (Go, .NET, gRPC, REST) enabling integration between the core VMS product and 3rd party analytics tools, empowering external developers.
  • Operated extensively within a Kubernetes environment, defining deployment strategies and optimizing distributed services for high throughput and reliability.
  • Mentored two junior developers, guiding their technical growth and contributions.
  • Contributed to team building as part of the events committee.

Senior Software Engineer @ Xero

Apr 2021 – Apr 2022

Auckland, New Zealand

  • Architected and delivered a mission-critical, microservices-based integration layer (using .NET Core, Go, Lambda, DynamoDB, S3) between Xero's accounting platform and Shopify, automating key financial workflows for numerous customers.
  • Collaborated closely with multiple Xero teams to ensure seamless end-to-end functionality.
  • Managed cloud infrastructure via Terraform, promoting Infrastructure as Code practices.

Solutions Developer / Lead / Architect @ Sandfield

Mar 2015 – Apr 2022

Auckland, New Zealand

  • Led development of a comprehensive transport management platform (.NET Framework/Core, SQL Server, React) serving 100+ enterprise clients across New Zealand and Australia.
  • Architected and implemented a multi-tenant SaaS solution handling millions of transactions, ensuring 99.9% uptime and sub-second response times.
  • Designed and built RESTful APIs and integration layers connecting with 50+ third-party systems (payment gateways, mapping services, government APIs).
  • Led a team of 4 developers on a new transport product initiative, implementing automated CI/CD pipelines and database migration strategies.
  • Championed engineering best practices through knowledge transfer sessions on SOLID principles, Clean Architecture, and Microservices patterns.
  • Mentored interns as part of the company's official program.

Senior Software Engineer @ Fiscalgis

Aug 2013 – Sep 2014

Buenos Aires, Argentina

  • Led development (team of 5) for a GIS application (web/desktop) for government agencies using .NET Framework and Oracle DB, managing large cadastral datasets.
  • Successfully designed and implemented an internal time-tracking tool (.NET, EF, SQL Server).

Software Engineer / Lead @ Infomeda

Jun 2010 – Jun 2013

Buenos Aires, Argentina

  • Led a small team (3 developers) focused on integrations for advertising industry clients (.NET Framework, EF, SQL Server).
  • Successfully developed and delivered a URL shortening product integrating with the Google+ API.

Junior Software Engineer @ Snoop Consulting

Oct 2009 – Jun 2010

La Plata, Argentina

  • Developed features for a financial industry client using Java, Spring, Hibernate, and DB2, gaining exposure to different technology stacks.

Junior Software Engineer / De Facto Lead @ Softtek

Oct 2008 – Oct 2009

La Plata, Argentina

  • Rapidly progressed from learning .NET/C#/ASP.NET Web Forms to taking lead responsibility (team of 3) for integrating with SAP via SOAP web services after the senior lead departed.
  • Engaged directly with the client for requirements gathering for a major refrigeration industry client. Became a key technical referent for the team.

Technical Skills

Core Languages

C# (.NET Core/Framework) Go JavaScript/TypeScript Python

Frontend

React React Native HTML5/CSS3 Svelte Phaser

Backend & Architecture

Microservices gRPC REST APIs Event-Driven Systems Domain-Driven Design FastAPI

Cloud & DevOps

AWS Kubernetes Docker Terraform CI/CD Azure DevOps Linux GitHub Actions (self-hosted, GARM, Incus) Cloudflare (Tunnel, Access)

Databases

SQL Server DynamoDB Redis PostgreSQL SQLite

Observability

Datadog Sentry Prometheus Grafana Loki Tempo Alerting Logging

AI & LLMs

LLM integration (llama.cpp) RAG & embeddings AI-assisted development (Claude Code)

Projects

Monkey Island homelab platform

Three self-hosted machines run my public sites, their databases and an AI agent in production: Docker Compose on bare metal behind Traefik, with public traffic arriving through Cloudflare Tunnel. Self-hosted GitHub Actions runners (GARM, one ephemeral Incus VM per job) build each image once; a deploy gate ships that exact digest to UAT, runs Playwright, and promotes the same digest to production. The platform also runs full LGTM observability with Telegram alerts, nightly backups copied offsite to Backblaze B2 with an append-only key, and a control panel that compares every service's version with GitHub and triggers pulls, stack updates and installers.

Docker Traefik Cloudflare GitHub Actions Incus Prometheus Grafana Loki Tempo Linux

Local AI stack and agent

llama.cpp serving Qwen3.5-9B on my own hardware, with per-client API keys and Prometheus metrics; it powers the guide assistant inside app.staysy.co. Next to it sit a RAG pipeline (an embeddings server and the Chroma vector database) and a Telegram AI agent on an isolated Docker network that can reach the model server but not the database, with its memory backed up nightly.

llama.cpp RAG Chroma Python Docker Telegram

Holarchy

Your personal AI agent on a USB stick. Plug it into any computer you own and your agent runs there, with everything it knows about you, and every copy keeps learning and shares what it learns with the others. Built and tested as a single static Go binary for Linux, macOS and Windows, it keeps its memory encrypted on the stick and in a private git repo with keys only you hold, learns append-only so that forgetting is a deliberate, recorded act, and runs every action through a three-layer sandbox: the model proposes, a rule-keeper checks it against your signed constitution, and only then does the agent act.

Go Cryptography Git LLM Agents Cross-platform

playthis.today arcade and The Game

playthis.today is an arcade of browser games, served as a static site that deploys on every merge to main. Alongside it, The Game (tg.playthis.today) is a viral Go and SQLite web app: open the link, lose The Game, then generate a shareable link to pass it on. Both are self-hosted; The Game adds rate limiting and a hardened security policy.

Go SQLite JavaScript HTML5 CSS3 Self-Hosted
Visit playthis.today

Wisp

A real-time multiplayer browser game with a Go backend and a Svelte frontend. Games live in memory on the server, and 2v2 and 3v3 matches can include AI opponents. Every merge to main deploys automatically.

Go Svelte Real-time Multiplayer
Play Wisp

Stray Paws

A browser game with a Go backend, a Phaser frontend and PostgreSQL storage. It is in UAT, open only to private testers, and ships through the same build-once, promote-by-digest pipeline as the homelab's other apps.

Go Phaser PostgreSQL Docker

Personal CV website

This site: a bilingual CV (English and Spanish) generated from JSON data into static pages and ATS-friendly PDFs, with the PDFs' text layer verified on every build. A private admin behind Cloudflare Access builds PDF versions tailored to specific roles from the same data.

Python FastAPI HTML5 CSS3 JavaScript Docker
github View on GitHub

Don't Let Me Die

A kind of fancy CLI quiz game where you keep your pet alive by answering questions correctly. Features interactive CLI menus, NPM package distribution, and questions fetched from Open Trivia Database. Built to practice creating NPM packages and interactive command-line interfaces.

JavaScript Node.js CLI NPM Inquirer Chalk Figlet
github View on GitHub

Education & Certifications

Academic Education

Master's Degree, Software Engineering

2012 – 2014

Universidad Nacional de La Plata (UNLP), Argentina

Focused on advanced software design patterns, architectural principles, software quality assurance, and project management methodologies, deepening the theoretical and practical aspects of building complex software systems.

Engineering Degree, Systems Information Engineering

2005 – 2011

Universidad Tecnológica Nacional (UTN), Argentina

Comprehensive 5-year engineering program covering foundational computer science, algorithms, data structures, database management, networking, operating systems, and the full software development lifecycle. Provided a strong analytical and problem-solving base.

Certifications & Specializations

Deep Learning Specialization

2017 – 2018

Coursera (deeplearning.ai)

In-depth specialization covering foundational and advanced neural networks, Convolutional Neural Networks (CNNs), Recurrent Neural Networks (RNNs), model tuning strategies, and practical applications of deep learning.

Self-Driving Car Engineer Nanodegree

2016 – 2017

Udacity

Hands-on program focused on the core components of autonomous vehicle technology, including computer vision, sensor fusion, localization, path planning, and control systems, utilizing relevant ML/DL techniques.