Guillermo Madariaga Sierra

Electronics engineer · Full-stack developer

Systems · Architecture · 2026

Engineering systems that can evolve.

A visual portfolio of maintainable products, architecture and practical development supported by AI.

Backend developer · Speed Solutions · 7+ years · .NET · Web · Mobile · AI-enabled delivery

Explore the work
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01 / Background

BACKGROUND / 01

Full-stack developer · Electronics background

From physical systems to digital products.

Electronics trained me to trace signals, understand constraints and respect the whole system. Software became the medium for turning that way of thinking into products that can evolve.

For more than seven years I have worked across backend, web and mobile products. At Speed Solutions I contribute as a backend developer and have maintained a .NET application for over four years, supporting its diagnosis, delivery and long-term evolution.

ELECTRONICS → SOFTWARE
7+years building software
.NETbackend specialization
Web · Mobile · Desktopproduct surfaces
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02 / Selected work

SELECTED WORK / 02

Selected work

Built across the stack.

A small selection of systems and products where architecture, performance and the user experience have to work together.

2026

Communication platform / Multi-surface

RemoteLink

A focused remote support product designed around reliable communication, presence and low-friction collaboration.

.NETASP.NET CoreSignalR.NET MAUI
Read case study
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03 / Selected work

SELECTED WORK / 02

Selected work

Work detail

Different surfaces, same discipline: clear contracts, useful abstractions and careful delivery.

2026

Developer tooling / Windows

DevProxy Studio

A modular reverse proxy for exposing local applications to a LAN while capturing, persisting and inspecting HTTP traffic.

.NET 10WinUI 3YARPSQLite
Read case study
05

More work

ADDITIONAL WORK / 02

More selected work

More work

Different surfaces, same discipline: clear contracts, useful abstractions and careful delivery.

2026

Mobile and device integration

RemotePad

A mobile control surface paired with a Windows service for remote input, screen capture and device-oriented workflows.

.NET MAUIAndroidWebSocket
Read case study

A small selection of systems and products where architecture, performance and the user experience have to work together.

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03 / Design principles

DESIGN PRINCIPLES / 03

Development approach

Elegant is useful when it lasts.

I use architecture as a tool for change: enough structure to protect the important parts, never ceremony for its own sake.

01

Boundaries first

Clear domain boundaries keep products adaptable, testable and easier to reason about.

02

Performance by design

Fast experiences come from deliberate data flow, small client payloads and non-blocking work.

03

Useful complexity

Architecture earns its place when it protects change, not when it adds ceremony.

07

Architecture

ARCHITECTURE / 03

A practical boundary map

FLOW ↓

Keep the core independent. Let the edges adapt.

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Presentation Web · API · desktop · mobile
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Application Use cases · orchestration · contracts
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Domain Rules · entities · events
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Infrastructure Data · HTTP · messaging · adapters

The domain should not know whether it is being called by a browser, a mobile client or a background process. Ports express intent; adapters handle the outside world.

See the approach in a real project
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04 / Stack

STACK / 04

Toolkit

Broad enough to connect the dots.

Specialized in .NET backend development, with experience across the surfaces and languages that make a product complete.

Backend

C# / .NET
ASP.NET Core
REST APIs
SignalR
SQL

Frontend

Astro
TypeScript
React
Responsive CSS
PWA
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08 / Development practice

ENGINEERING / 04

Toolkit

From implementation to delivery.

Specialized in .NET backend development, with experience across the surfaces and languages that make a product complete.

Mobile & desktop

Java
Kotlin
Flutter
.NET MAUI
Windows

Development practice

Clean Architecture
Hexagonal design
Git workflow
Azure & DevOps
Testing
Agile delivery
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05 / AI workflow

AI WORKFLOW / 05
AI

05 / AI workflow

Tools should amplify judgment, not replace it.

Since the early ChatGPT releases, I have explored models, agents, skills and automation as part of the development workflow — with deliberate review, clear constraints and ownership of the result.

06 / Contact

Let’s build something that can be understood.

A product, system or technical challenge is a good place to start a conversation.

Start a conversation