Production systems that ship and bill — and I publish the dead-ends, not just the wins.

Sole engineer on a legal-grade transcription platform: a Whisper + LLM pipeline with anti-hallucination guardrails on a nine-server fleet, the whole money chain wired in — invoicing, SEPA, dunning, reconciliation, fraud. On-call, real invoices. Not slideware.

Before that I built and ran a fully systematic global-macro fund — engineered the entire trading stack and took monthly volume from under $100M to $9B+ on a low-latency FIX path into LMAX. And before that, ~10 years reverse-engineering protocols and protections for the paid security press.

• Open-Alpha-Lab — an open quant research desk. I audit trading ideas in public and publish the verdict: edge or mirage. Study 01 takes apart the "stocks only go up overnight" anomaly — real signal, untradable — with a working paper, two notebooks and a reproducible engine. The view from someone who actually ran the fund.
• DS2-Anywhere — open Rust decoder for the Olympus DS2/DSS dictation format, locked for ten years. Retired a paid license in production; now driving it upstream into FFmpeg (ticket #6091, open since 2017).
• FLAC Detective — catches MP3s smuggled into lossless files. The good part is the honest ML write-up: four approaches that failed and an "AUC 0.99" false discovery I caught and killed.
• Prometheus-Station — solar Raspberry Pi serving offline Wikipedia over a long-range LoRa mesh, for when the grid isn't there.
• HAP-Revival — keeping Sony's HAP-Z1ES / HAP-S1 audiophile players alive after Sony walked away in 2021.
• Creabook — a book-generation engine.

Production-first, honest about uncertainty, allergic to cleverness that doesn't survive testing. I read FIX logs and Pascal with about equal pleasure.

A few contract engagements a year — systems that have to work, not demo: production LLM/Whisper pipelines (plus the billing infra most people skip), file-format and legacy reverse-engineering, trading & market-data plumbing (FIX, low-latency, backtest-to-production).

→ guillain@poulpe.us · FR / EN / ES · near Venice