Aitor Nain Mendoza Vallejo (naindev)
Madrid, Spain • Autonomous Software Architect • Backend, Deterministic Geometry & Production AI
I design and build fault-tolerant backend architectures, deterministic validation engines, and high-assurance AI integrations for systems where failure is not an option. My engineering approach enforces strict separation of concerns, formal specification before implementation (Spec-Driven Development), and mathematically verified domain invariants.
- Deterministic Computational Systems: Exact Boundary Representation (B-Rep) solid modeling via OpenCASCADE and CadQuery, domain-isolated 2-manifold topological mesh verification, and content-addressable artifact pipelines.
- Enterprise Backend Architecture: Hexagonal Architecture (Ports and Adapters), Clean Architecture, Domain-Driven Design (DDD), and CQRS across asynchronous distributed systems.
- Production AI Integrations: Deterministic parameter extraction, robust fallback mechanisms (rule-based offline parsers alongside LLMs), and strict Pydantic JSON contracts.
- High-Performance Persistence: Complex relational modeling, multi-tenant isolation, auditing, and high-throughput concurrency control (ETag, rowversion) across Microsoft SQL Server, PostgreSQL, and SQLite.
All projects are engineered with verifiable evidence, automated test suites, and 1-click cloud demonstrations:
| System / Repository | Primary Stack | Architecture & Verification | Live Demonstration |
|---|---|---|---|
| ParametriCAD AI | Python 3.12, FastAPI, OpenCASCADE, CadQuery, Three.js, React 19, TypeScript, Docker | Deterministic CAD Engine & 3D Web Viewer. Constructs exact B-Rep solids, enforces physical fabricability invariants, verifies topological mesh quality (watertightness, 2-manifoldness, normal orientation), and exports 5 engineering formats (GLB, glTF, STEP, STL, DXF) with SHA-256 content addressing. 261 automated tests including Hypothesis property-based testing. | Open 3D App Source Code |
| Microservice Notifications Core | .NET 10, C#, MassTransit, RabbitMQ, MailKit, Clean Architecture, Docker | Sub-50ms Asynchronous Dispatcher. Decoupled notification microservice built on message queues with dead-letter exchanges, exponential backoff retries, and cluster isolation. | Interactive Demo Source Code |
| Financial Policy Operations API | .NET 10, C#, EF Core 10, SQL Server, Clean Architecture, DDD, Azure | Enterprise Lifecycle Engine. Manages insurance policy state transitions (Draft -> Active -> Cancelled), tenant isolation, and strict optimistic concurrency control via ETags. |
Live Swagger API Source Code |
| Civil Service Examination Platform (TAI) | .NET 10, C#, Dapper, SQL Server, React 19, TypeScript | High-Throughput Assessment System. Real-time examination evaluation engine executing official INAP scoring algorithms (+1.0 / -0.33) with sub-10ms query response times and responsive SPA interface. | Test Platform Source Code |
| Driving School Financial & Ops Engine | Python 3.12, Pydantic v2, SQLAlchemy, SQLite, Streamlit | Operational & Ledger Dashboard. Business accounting platform with deterministic financial validation, automatic balance reconciliations, and PDF invoice generation. | Launch Demo Source Code |
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| Presentation & Ingestion |
| React 19 (Three.js / WebGL) | Astro | OpenAPI / REST | Asynchronous Workers |
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| Application Orchestration & Ports |
| Spec-Driven Pipelines | CQRS Mediators | Domain Events | MassTransit Queues |
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| Domain Core & Pure Logic |
| Boundary Invariants | Pydantic Contracts | Topological Verification | Entities |
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| Infrastructure & External Adapters |
| OpenCASCADE (CadQuery) | SQL Server (T-SQL) | PostgreSQL | RabbitMQ | Filesystem |
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- Spec-Driven Development (SDD): Changes originate in explicit specifications (
charter,requirementsin EARS format,architecturewith Mermaid diagrams,data-model,ADRs, andtraceability), never directly in unconstrained code. - Deterministic Quality & Zero Assumptions: All geometric invariants and business rules are validated by automated property-based test suites. No capability is claimed without reproducible automated verification.
- Decoupled Domain Layers: The presentation layer captures input and renders responses; it never calculates business logic, enforces business invariants, or accesses persistence.
- Resilient & Cost-Conscious Infrastructure: Low-overhead architectures designed for minimal compute footprints, high cache hit rates (content addressing), and horizontal process isolation over unsafe threading.
Available for independent software architecture consulting, mission-critical backend design, and deterministic computational systems:
- Portfolio & Case Studies: www.naindev.com
- Email: contact@naindev.com
- LinkedIn: Aitor Nain Mendoza Vallejo
- GitHub: github.com/Nain9Dev