Hi, my name is
David Buitrago.
I build reliable systems._
I'm a software engineer and tech lead based in Madrid, building backend systems, APIs, and internal products.
Estimated operational impact
Estimated from before-and-after process timings and annual workflow volumes.
01.About Me
Hi, I’m David, a software engineer and tech lead based in Madrid.
Over the past 10 years, I’ve built and supported enterprise software, integrations, and internal products. At Qualitas Funds, I help shape the technology behind investment operations, turning complex processes such as onboarding, reporting, and calculations into reliable systems.
Throughout my career, I’ve moved between different technologies and problem spaces: .NET, SQL, Azure, TypeScript, Node.js, NestJS, React, and Next.js. I enjoy working across backend services, APIs, data modelling, cloud infrastructure, and product requirements — wherever the problem needs attention.
I care about clear system boundaries, maintainable code, and software that teams can understand, operate, and improve over time.
03.Skills
Backend systems, data workflows, cloud infrastructure, and technical leadership.
Backend Engineering
- Node.js · TypeScript · NestJS · React · Next.js · .NET Core · C# · PostgreSQL · REST APIs
- SQL and data modelling · Azure SQL · SQL Server · MongoDB
- Asynchronous workflows · Data integrations · Background jobs
Cloud & Infrastructure
- Azure (App Services · SQL · Storage · Networking · Entra ID · DevOps)
- Docker · GitHub Actions · Azure DevOps · CI/CD
- Production operations · Server & network management
System Design & Quality
- Scalable service design · API design · Data modelling
- Testing · Code reviews · Observability · Technical documentation
Architecture & Leadership
- Solution architecture · End-to-end ownership · Stakeholder collaboration
- Team mentoring · Code reviews · Delivery planning
04.Where I’ve Worked
Tech Lead @ Qualitas Funds
Mar 2021 – Present · 4+ years · Madrid, Spain
- Own technology architecture across applications, Azure infrastructure, databases, integrations, and development workflows for an investment-management business.
- Designed and delivered automated workflows for commission calculations, investor onboarding, reporting, and operational processes, with Azure SQL as a core system of record.
- Lead end-to-end technical delivery: turn stakeholder requirements into pragmatic designs, coordinate implementation, and improve reliability and maintainability in production.
- Mentor developers through code review and architectural guidance; establish shared standards for documentation, delivery, and operational ownership.
Stack: .NET Core · Azure SQL · React · TypeScript · REST APIs · Docker · Azure DevOps · Azure (App Services · Networking · Storage · Entra ID)
SharePoint Development Engineer @ Syntax Informática
2019 – Mar 2021 · 2 years · Madrid, Spain
- Delivered custom SharePoint solutions and corporate intranet platforms for enterprise clients across multiple industries, including full digital transformation projects.
- Designed software architectures for complex SharePoint customizations, integrating with Microsoft 365 services, custom APIs, and legacy enterprise systems.
- Led the technical delivery of intranet projects from requirements through deployment, working directly with clients to align technology choices with business needs.
Stack: SharePoint · Microsoft 365 · .NET · SPFx · Azure AD · Power Platform
Software Development Engineer @ Intergrupo
Oct 2017 – Mar 2019 · 1.5 years
- Designed and developed software architectures for multiple enterprise projects, primarily within the Microsoft ecosystem (.NET, SharePoint, SQL Server).
- Built web applications using React for client-facing interfaces, combined with .NET backends and SQL Server data layers.
- Collaborated on architecture definitions for projects of varying scale, from departmental tools to company-wide platforms.
Stack: .NET · SharePoint · SQL Server · React · REST APIs
Technical Lead · Digital Transformation Consultant @ Conocimiento Corporativo
Mar 2014 – Oct 2017 · 3.5 years
- Advised enterprise clients on technology strategy and digital transformation, helping them select and implement the right platforms for their business needs — predominantly Microsoft 365 and SharePoint ecosystems.
- Led technical projects from discovery through delivery, working closely with stakeholders to translate business requirements into architectural decisions.
- Established myself as a trusted technical reference for clients navigating the transition from on-premise infrastructure to cloud-based collaboration platforms.
Stack: SharePoint · Office 365 · .NET · SQL Server · Solution architecture
05.Some Things I’ve Built
Featured Project
ADSIS
adsis.ai +B2B SaaS platform with reliable asynchronous workflows
ADSIS is a B2B SaaS platform I designed and built from scratch for performance-marketing teams. It combines a TypeScript frontend with an ASP.NET Core backend and PostgreSQL-based data layer, giving customers a structured workflow for creating campaign assets.
The product handles multi-step asynchronous work and a credit system with atomic deductions and an immutable transaction ledger. Those constraints shaped the data model and background-processing design from the beginning.
I own its architecture, backend, frontend, infrastructure, and CI/CD. It runs in production on Docker with a reverse proxy, automated certificates, and repeatable deployment workflows.
- ASP.NET Core 9
- React 19
- TypeScript
- Supabase (Postgres + Auth)
- Hangfire
- Docker
- GitHub Actions
- Tailwind CSS v4
- B2B SaaS product with structured campaign-creation workflows
- Credit system with atomic deductions and immutable transaction ledger
- Asynchronous background processing with Hangfire for multi-step workflows
1,540hestimated annual capacity releasedAcross five operational workflows, based on before-and-after timings and annual volume.
Featured Project
Operations workflow automation
Reliable workflow automation for investment-management processes
At Qualitas Funds, I have designed workflow automation around business and operational processes, including commission calculations, investor onboarding, and reporting. The focus is reducing manual work while preserving traceability and dependable handoffs between systems.
Across Capital Accounts, payments, onboarding, capital events, and valuations, the platform reduced execution time by an estimated 50% to 65%. These systems connect existing data sources and business processes through explicit workflows, database-backed state, and production infrastructure.
- N8N
- Azure SQL
- Azure
- .NET Core
- REST APIs
- Docker
- Capital Accounts: 10 to 4 working days (−60%, ~480 hours/year)
- Payments: 20 to 7 minutes (−65%, ~390 hours/year)
- Investor onboarding: 45 to 20 minutes per record (−56%, ~167 hours/year)
Featured Project
Enterprise integration delivery
Custom platforms connecting business processes and legacy systems
Across Syntax Informática and Intergrupo, I designed and delivered enterprise platforms that connected Microsoft 365, SharePoint, custom APIs, .NET services, and SQL Server data layers.
The work covered the full lifecycle from requirements and system design to implementation and deployment, collaborating directly with clients and stakeholders to make complex systems usable and maintainable.
- .NET
- SQL Server
- React
- REST APIs
- SharePoint
- Microsoft 365
- API and legacy-system integrations for enterprise customers
- Architecture and technical delivery from requirements to deployment
- React frontends backed by .NET services and SQL Server data layers
Featured Project
obsidian-ai-assistant
Semantic search and AI Q&A for your Obsidian vault
An AI assistant for Obsidian vaults that goes beyond keyword search. Documents are ingested, chunked, and embedded into a Qdrant vector database via an N8N pipeline. A conversational interface lets you ask questions across your entire knowledge base and get answers grounded in your own notes — with source references.
Built for my personal knowledge management workflow, where I maintain a vault of several thousand notes synced to GitHub.
- N8N
- Qdrant
- OpenAI / Ollama
- Docker
- Python
- Obsidian
- Automatic vault ingestion via N8N workflow (file watcher → chunker → embedder)
- Semantic search powered by a vector database (Qdrant by default, swappable) and OpenAI embeddings
- Conversational Q&A with source attribution
06.Other Noteworthy Projects
portfolio-v2
This portfolio — built with Next.js and Tailwind, inspired by Brittany Chiang's v4
- Next.js
- Tailwind
- TypeScript
vector-local-ai
Experiment reviving an Anki Vector robot with local AI using Wire-Pod and Ollama
- Python
- Ollama
- Wire-Pod
- Docker
donna
Personal AI assistant with persistent memory, voice interface, and Obsidian integration
- OpenClaw
- ElevenLabs
- N8N
- Honcho
07. What’s Next?
Get In Touch
I’m open to senior engineering opportunities where reliable systems, thoughtful architecture, and close collaboration with product teams make a meaningful difference. If that sounds like your team, I’d be glad to talk.
Say hello