João Raul Furtado Lucas

Forward deployed engineer · Porto Alegre, BR

I build back-end systems that have to stay correct under load. Market data at Nelogica, then payments and e-invoicing at Singular. Now at Telepatia, putting clinical AI inside the hospital systems it has to work with.

Impact

Case studies

Approval workflow for high-value transactions

Singular · 2025–2026 · .NET, Azure, SQL Server

Problem

On a platform serving ~15,000 users, every transaction followed the same path regardless of value, and nobody could reliably say who signed off on what.

Ownership

Me: workflow design & buildTeam: audit trailClient: limits per unit

Decisions

  • Threshold-based routing. Only transactions above a limit enter the flow.
  • Limits per business unit, set by the client's management, no deploy needed.
  • Full audit trail. Who decided, why, and who issued the invoice.

Outcome

R$230M+ a month under governance. Every high-value decision has a named owner and a recorded reason.

Reconciliation pipeline redesign

Singular · 2026 · .NET, SQL Server, Redis

Problem

The pipeline exhausted the connection pool. Requests timed out and contract balances stopped updating.

Ownership

Me: root cause & redesign

Decisions

  • 12 Redis-backed workers, sized from work time, run budget and spare connections.
  • Batching: ~500K → ~100K queries per run.
  • Cache for rarely-changing reference data.

Outcome

Peak connections ~400 → 12, runtime 40 → 15 minutes.

End-of-day closing for an asset manager

Nelogica · 2024–2025 · SQL Server, Delphi, .NET

Problem

The closing processed every record one at a time, on 5–6M records a day.

Ownership

Me: led the performance workTeam: diagnosis & fixes

Decisions

  • Execution plans first, then targeted indexes.
  • Batched writes instead of row-by-row. The biggest win.

Outcome

−80% execution time.

Things I made

On AI: agents help me write and test code. The decisions, reviews and numbers here are mine.

Writing

Experience