CARDBOARD PROTOCOL

ISSUE 001

2022 — PRESENT

ARCHIVE / HM-001

HÉLIO
MATONDO

FULL-STACK SOFTWARE ENGINEER
& SYSTEMS ARCHITECT

A graphic novel about systems, code and ideas.

READ THE STORY VIEW PROJECTS

LUANDA / WORLDWIDE

An archival systems blueprint on cardboard
SCROLL TO OPEN ↓

CHAPTER 01

ORIGIN

A short record of how an interest in software became an interest in systems.

P. 01

FIRST SIGNAL

2022 — a practical curiosity for how digital products are assembled, tested and made useful.

P. 02

WIDER FRAME

Web applications opened into databases, networks, infrastructure and the boundaries between services.

P. 03

THE WORK

I design and build scalable digital systems, combining software engineering, product thinking and technical architecture.

CHAPTER 02

THE ENGINEER

Capabilities mapped as a working system, not a list of percentages.

01 / Interface

Interface engineering

  • React
  • Next.js
  • TypeScript
  • Tailwind CSS
  • GSAP
  • HTML
  • CSS
02 / Backend

Backend systems

  • Node.js
  • Express
  • Java
  • Spring Boot
  • Python
  • Rust
  • REST APIs
03 / Data

Data

  • PostgreSQL
  • MySQL
  • Redis
  • Supabase
  • PostGIS
  • Prisma
04 / Architecture

Architecture

  • Clean Architecture
  • Domain-Driven Design
  • Event-Driven Architecture
  • Distributed Systems
  • Microservices
Core / Infrastructure

Infrastructure

  • Docker
  • Linux
  • GitHub Actions
  • Vercel
  • TCP/IP
  • VLANs
  • Cisco routing & switching

2022–2023

Foundation

Started building web applications and studying software fundamentals.

2023–2024

Systems

Expanded into full-stack systems, relational databases and networking.

2024–2025

Structure

Worked on larger platforms, product architecture and developer tooling.

2025–Present

Scale

Exploring enterprise systems, distributed architecture, civic technology and digital ecosystems.

CHAPTER 03

SELECTED SYSTEMS

Public evidence first. Each case is presented as a system, with its current state stated plainly.

CASE 001

Civic technology / mobile

MVP

KANDA

A community mobile application for reporting and following urban occurrences in Angola.

PROBLEM

A community mobile application for reporting and following urban occurrences in Angola.

APPROACH

A focused mobile flow for reporting, map visibility and lightweight community status instead of an overbuilt municipal dashboard.

RESULT

A public MVP that frames civic reporting as a clear, mobile-native workflow.

ARCHITECTURE
  • Phone-first reporting
  • Local persistence
  • Occurrence map
  • Expo routing
CASE 002

Distributed infrastructure / research

Foundation scaffold

VOIDNET

An experimental decentralized network ecosystem built above existing internet transport.

PROBLEM

An experimental decentralized network ecosystem built above existing internet transport.

APPROACH

Establish typed protocol, identity, transport and runtime boundaries before pursuing a polished application surface.

RESULT

A documented Phase 1 foundation with node, CLI, chat and browser shells; presented accurately as exploratory infrastructure.

ARCHITECTURE
  • libp2p + QUIC transport
  • Ed25519 identity
  • Typed frames
  • DNS and runtime boundaries
CASE 003

Local-first communication

v0.1.1

KAYA CLI

An offline-first decentralized communication system for local networks, with optional direct and relay paths.

PROBLEM

An offline-first decentralized communication system for local networks, with optional direct and relay paths.

APPROACH

Separate protocol, transport, security, persistence and operator UI into explicit Rust crates.

RESULT

A modular local-network communication system with public documentation and release artifacts.

ARCHITECTURE
  • UDP multicast discovery
  • Encrypted direct messages
  • Optional relay
  • Local persistence
CASE 004

Enterprise platform / monorepo

Foundation in progress

AFRICAN BUSINESS NETWORK

A digital ecosystem conceived for African businesses to operate and grow from one coordinated platform.

PROBLEM

A digital ecosystem conceived for African businesses to operate and grow from one coordinated platform.

APPROACH

Define domain, permissions, events, observability and infrastructure as first-class platform concerns.

RESULT

An executable monorepo and substantial enterprise documentation; broader business modules remain intentionally out of scope.

ARCHITECTURE
  • Next.js + NestJS apps
  • Identity + organization core
  • PostgreSQL + Redis
  • Domain packages and ADRs
CASE 005

Public finance systems

Full-stack system

SGFE

A system for the management, execution, monitoring and auditing of public finance operations.

PROBLEM

A system for the management, execution, monitoring and auditing of public finance operations.

APPROACH

Model fiscal workflows, access control and auditability across a dedicated frontend and Java backend.

RESULT

A public codebase with documented domain boundaries and validation commands.

ARCHITECTURE
  • Budget execution domain
  • RBAC + audit logs
  • JWT session model
  • Migration-managed data

CHAPTER 04

ENGINEERING PROCESS

A repeatable investigation sequence for products that cannot be solved with a template.

SYSTEM MAP / 01

WEBAPI GATEWAYSERVICE BOUNDARYPOSTGRESEVENT QUEUEWORKER

Validate at the edge. Emit events after persistence. Observe every boundary.

PROTOCOL / 06
  1. 01Observe→
  2. 02Model→
  3. 03Architect→
  4. 04Build→
  5. 05Validate→
  6. 06Refine→

Every handoff receives an explicit constraint, an observable boundary and a validation path.

SAFE SNIPPET
type Event = { id: string; kind: "report.created" };

export async function publish(event: Event) {
  validate(event);
  await outbox.store(event);
  await queue.enqueue(event.id);
}

CHAPTER 05

EXPERIMENTS

Smaller files pinned to the research wall: useful signals, not filler.

LAB 01

Learning infrastructure

Research product

RECALL

A knowledge-base workflow for video courses, transcription, curriculum reconstruction and search.

Included as an experiment because its asynchronous ingestion architecture broadens the systems narrative.

LAB 02

Queue management / PWA

Experiment

KUILU

A digital queue-management concept for physical establishments.

Placed in experiments: the public repository documents a coherent scope, but it is not presented as a flagship system.

ARCHIVE NOTE

This issue documents public work only. Each entry links to evidence that can be independently reviewed.

CHAPTER 06

CONTACT

End of issue. Beginning of a difficult system.