
MARCOS VILLALBA Senior Software Engineer \| .NET / Backend / Cloud Paraguay (UTC-3) \| Remote \| US business-hours overlap \| Contractor/C2C \| No sponsorship required +595 984 104 237 \| marcosariel.villalba@gmail.com \| LinkedIn PROFESSIONAL SUMMARY Senior software engineer and Google Cloud Professional Cloud Architect with 5+ years building production .NET/backend and cloud systems, including US consultancy work since January 2024. Led a 6-person team at FortyAU, delivered notification infrastructure for 350+ partner organizations, and stabilized the Concertación Nacional election-results platform on election day by splitting a failing sync into 18 department-specific workers that processed 1.3M+ vote updates. CORE STRENGTHS Backend & Delivery: .NET/backend architecture, REST APIs, integrations, authentication flows, requirements discovery, scoping, client and stakeholder management, end-to-end delivery, team leadership Languages & Frameworks: C#/.NET, ASP.NET Core, Entity Framework Core, Python, FastAPI, TypeScript, React, Blazor Cloud, Data & Tools: GCP (Professional Cloud Architect), Azure, AWS, Docker, Terraform, CI/CD, Git, Claude Code, Codex, SQL, PostgreSQL/pgvector, Firebase, Databricks PROFESSIONAL EXPERIENCE Senior .NET Developer Kubikware (software consultancy) \| Remote (US) July 2025 - Present Stack: .NET, React, Azure, Databricks Migrated authentication to Azure B2C with custom policies and streamlined the client authentication flow. Made cross-system event ingestion idempotent by deriving internal UUIDv8 IDs from stable federated IDs, so duplicate and out-of-order create events upsert to the same mapped entity. Built a strongly typed .NET query builder over the Databricks SQL API, reducing query-construction errors for analytics features. Team Lead & Senior .NET Developer FortyAU (Nashville software consultancy; healthcare & fintech) \| Remote (US) January 2024 - July 2025 Stack: .NET, Django, Python, React PWA Promoted to Team Lead after 8 months; led a 6-person cross-functional team and owned product scope, releases, acceptance criteria, sprint priorities, and direct client communication. Built a custom .NET background task runner (IHostedService) with bounded concurrency, a backpressure queue, and graceful shutdown, powering time zone-aware notification delivery (AWS EventBridge Scheduler) to 350+ partner organizations. Built a Terraform-managed GCP email pipeline (Cloud Scheduler to Cloud Tasks) to generate PandaDoc contracts asynchronously; supported Dwolla payment ledger reconciliation workflows. Full-Stack Engineer Concertación Nacional (Paraguay) - Election Results Platform \| Direct contract, part-time December 2022 - April 2023 Stack: .NET, Blazor WebAssembly, Azure, GCP, Firebase Stabilized the platform live on election day by partitioning a failing single-worker sync into 18 department-specific workers, processing 1.3M+ vote updates. Built fuzzy-matching utilities (Levenshtein and name-token scoring) to query and validate voter records in .NET. Owned the four-month build as the sole engineer, delivering the backend API and analytics dashboard end to end under election deadlines. Technical Lead & Full-Stack Developer Creadores (software agency) April 2021 - December 2023 Stack: C#, .NET, Flutter, Blazor Joined as a developer and was promoted into technical leadership in 2022, owning client discovery, scope, and delivery while staying hands-on across backend features. Led delivery of a real-time grocery delivery app (Flutter, WebSockets) and a cattle auction platform (Blazor/.NET) from client requirements through launch as the primary client and product contact. Delivered 6+ custom products across web and mobile, translating client needs into shipped software. ADDITIONAL AI WORK Technical Consultant (Software Engineering AI Training) \| micro1 (contract) 2026 Applied software-engineering domain expertise to support AI training focused on technical accuracy and reasoning quality. Engineering Intelligence (solo AI prototype) 2026 \| Stack: FastAPI, .NET, React, PostgreSQL (pgvector + BM25), Modal, Railway Prototyped an AI document-intelligence workflow that lets users upload sources, choose a template, review cited claims, and export a draft deliverable. Implemented a multilingual RAG pipeline: hybrid retrieval, cross-encoder reranking, and a per-claim verifier that checks each generated claim against its sources for grounding. Built a document ingestion service with GPU OCR on Modal, using memory snapshots to cut cold starts. EDUCATION & CERTIFICATIONS Google Cloud Professional Cloud Architect (2025) Mechatronics Engineer - Facultad de Ingeniería de la Universidad Nacional de Asunción (2021) LANGUAGES English: Fluent Spanish: Native

MARCOS VILLALBA

PROFESSIONAL SUMMARY

Senior software engineer and Google Cloud Professional Cloud Architect with 5+ years building production .NET/backend and cloud systems, including US consultancy work since January 2024. Led a 6-person team at FortyAU, delivered notification infrastructure for 350+ partner organizations, and stabilized the Concertación Nacional election-results platform on election day by splitting a failing sync into 18 department-specific workers that processed 1.3M+ vote updates.

CORE STRENGTHS

Backend & Delivery: .NET/backend architecture, REST APIs, integrations, authentication flows, requirements discovery, scoping, client and stakeholder management, end-to-end delivery, team leadership
Languages & Frameworks: C#/.NET, ASP.NET Core, Entity Framework Core, Python, FastAPI, TypeScript, React, Blazor
Cloud, Data & Tools: GCP (Professional Cloud Architect), Azure, AWS, Docker, Terraform, CI/CD, Git, Claude Code, Codex, SQL, PostgreSQL/pgvector, Firebase, Databricks

PROFESSIONAL EXPERIENCE

Senior .NET Developer

Kubikware (software consultancy) | Remote (US) July 2025 - Present

Stack: .NET, React, Azure, Databricks
Migrated authentication to Azure B2C with custom policies and streamlined the client authentication flow.
Made cross-system event ingestion idempotent by deriving internal UUIDv8 IDs from stable federated IDs, so duplicate and out-of-order create events upsert to the same mapped entity.
Built a strongly typed .NET query builder over the Databricks SQL API, reducing query-construction errors for analytics features.

Team Lead & Senior .NET Developer

FortyAU (Nashville software consultancy; healthcare & fintech) | Remote (US) January 2024 - July 2025

Stack: .NET, Django, Python, React PWA
Promoted to Team Lead after 8 months; led a 6-person cross-functional team and owned product scope, releases, acceptance criteria, sprint priorities, and direct client communication.
Built a custom .NET background task runner (IHostedService) with bounded concurrency, a backpressure queue, and graceful shutdown, powering time zone-aware notification delivery (AWS EventBridge Scheduler) to 350+ partner organizations.
Built a Terraform-managed GCP email pipeline (Cloud Scheduler to Cloud Tasks) to generate PandaDoc contracts asynchronously; supported Dwolla payment ledger reconciliation workflows.

Full-Stack Engineer

Concertación Nacional (Paraguay) - Election Results Platform | Direct contract, part-time December 2022 - April 2023

Stack: .NET, Blazor WebAssembly, Azure, GCP, Firebase
Stabilized the platform live on election day by partitioning a failing single-worker sync into 18 department-specific workers, processing 1.3M+ vote updates.
Built fuzzy-matching utilities (Levenshtein and name-token scoring) to query and validate voter records in .NET.
Owned the four-month build as the sole engineer, delivering the backend API and analytics dashboard end to end under election deadlines.

Technical Lead & Full-Stack Developer

Creadores (software agency) April 2021 - December 2023

Stack: C#, .NET, Flutter, Blazor
Joined as a developer and was promoted into technical leadership in 2022, owning client discovery, scope, and delivery while staying hands-on across backend features.
Led delivery of a real-time grocery delivery app (Flutter, WebSockets) and a cattle auction platform (Blazor/.NET) from client requirements through launch as the primary client and product contact.
Delivered 6+ custom products across web and mobile, translating client needs into shipped software.

ADDITIONAL AI WORK

Technical Consultant (Software Engineering AI Training) | micro1 (contract) 2026

Applied software-engineering domain expertise to support AI training focused on technical accuracy and reasoning quality.

Engineering Intelligence (solo AI prototype) 2026 | Stack: FastAPI, .NET, React, PostgreSQL (pgvector + BM25), Modal, Railway

Prototyped an AI document-intelligence workflow that lets users upload sources, choose a template, review cited claims, and export a draft deliverable.
Implemented a multilingual RAG pipeline: hybrid retrieval, cross-encoder reranking, and a per-claim verifier that checks each generated claim against its sources for grounding.
Built a document ingestion service with GPU OCR on Modal, using memory snapshots to cut cold starts.

EDUCATION & CERTIFICATIONS

Google Cloud Professional Cloud Architect (2025)
Mechatronics Engineer - Facultad de Ingeniería de la Universidad Nacional de Asunción (2021)

LANGUAGES

English: Fluent
Spanish: Native