10/13/2026 updated
DC
100 % available
Software Architect · Architecture, Performance and Modernization
Aveiro, Portugal
Only remote
ASP.NET.NET FrameworkSoftware as a ServiceData ArchitecturePostgreSQLLegacy System Migration WorkbenchMicrosoft SQL ServersSoftware ArchitectureSwaggerOpenapi.NET CoreLow LatencyApi DesignSoftware PerformanceDocker
I've spent 14+ years building and leading production software in long-running product roles rather than short contracts: multi-tenant SaaS, a manufacturing execution system running in plants across several industries, and a core banking solution. I haven't just made architecture decisions. I've lived with their consequences for years.
What I've done:
- Modernized legacy .NET systems in production without stopping product development: .NET Framework to - .NET Core, desktop to web, SQL Server to PostgreSQL, on-premise to cloud
- Stabilized products buried under bugs and conflicting features by fixing the domain and process behind them, not just the code
- Owned delivery end to end, from requirements and estimates to releases: built CI/CD, code review and QA into the workflow, cutting manual release steps and production incidents, including releases that had to fit a one-hour plant stop without breaking traceability
- Merged duplicated code into shared components, reducing errors and making the product easier to change
- Built an automated production scheduler that turns customer orders into machine schedules and raw-material requirements, replacing spreadsheet planning
- Rewrote slow hierarchical queries and indexing as plant data grew
- Worked out what undocumented systems and databases actually do, then integrated or replaced them
Where I'm most useful:
- A system that has become hard to change
- Database, API or search bottlenecks as data and tenants grow
- A legacy .NET product that blocks new work and has to be modernized step by step while it keeps shipping
- An architecture decision with large consequences: a migration, a rewrite, cloud vs on-premise
- A team without senior technical direction
- MCP servers that expose existing systems to AI agents, document extraction and search with source citations, and automated data pipelines, as one part of a larger business system.
Technical skills:
C#, .NET Core, .NET Framework, ASP.NET, Web API, WCF, REST API design, OpenAPI/Swagger · Microsoft SQL Server, T-SQL, PostgreSQL, query optimization, indexing, data modeling, SQL Server → PostgreSQL migration · Multi-tenant SaaS architecture, high-volume processing, search architecture, low-latency APIs · AWS, S3, Docker, load-balanced deployments, CI/CD, cloud vs. on-premise decisions · System integration, third-party and legacy APIs, ERP integration, Python, FastAPI, data pipelines, LLM structured extraction, RAG and hybrid search, embeddings, local LLMs, workflow automation · Architecture review, technical due diligence, reverse-engineering undocumented systems and databases, vendor proposal review, security and GDPR review · React front-ends as part of full systems.
Experience
Professional experience10+ years
Freelancer since2026
Languages
EnglishFluentPortugueseNative speaker