Paris, France
Retail Store Manager & Independent Developer
Ten years in specialty retail, five of them running stores in Paris — most recently opening one from an empty unit. I came to the shop floor from software engineering, and never really left it: I still build the tools my teams use.
Opened from an empty unit. Revenue grew roughly +69% in the four months following launch, outpacing the store network while comparable stores fell over the same window. 5.0★ across 213 reviews.
Grew revenue about +36% over the five-year tenure (~7.9% a year) across 64,000 transactions, ahead of the store network over the same period. Review average rose from 4.54 to 4.77, closing at 4.9★ across 364 reviews.
Sales Advisor at Vapostore (2016–2020) before taking over a store, and Junior R&D Developer at Docubase Systems (2014–2016), building in Java, Spring, AngularJS and NoSQL. The engineering background never went away — it became the tooling my teams now run on.
Figures are trading-day normalized and reconciled against two independent data sources — not marketing numbers. Full audited detail available on request.
The real dashboard — figures swapped for this screenshot
A multi-tenant revenue, stock and analytics dashboard covering four retail stores, grown into a small SaaS product.
Over thirty shipped features: live revenue leaderboard, expiry/DLUO tracking, cross-store transfers writing into a live point-of-sale system, and an analytics suite (sales heatmaps, RFM segmentation, revenue forecasting). Found and fixed a seven-year-old double-counting bug in production data by reconciling it to the cent against register logs.
Flask · PostgreSQL · SQLite · pytest · canary deploys
A password-gated one-pager built for exactly this purpose: showing vetted recruiters the audited numbers behind a retail-management career.
The real page, decrypted — figures swapped for this screenshot
A build pipeline reads raw sales data, seals it into a single self-contained static page, and encrypts the payload client-side (AES-256-GCM, password-derived key, 310,000 PBKDF2 iterations). A custom build step scans the output and aborts if any sensitive figure would leak into the static HTML — it caught a real leak during development.
Python · Web Crypto API · zero JS frameworks
A live match-schedule and box-score tracker aggregating five different sports data APIs, designed and shipped in a single day.
Live at esports.williampereira.fr
A rate-limit incident on launch day was traced to concurrent workers multiplying outbound API pressure — fixed by an architecture change (single worker, in-memory TTL cache) rather than throwing more infrastructure at it.
Flask · vanilla JS · multi-API aggregation
A zero-dependency tool server that lets my coding assistant offload work to spare compute on my home network instead of the cloud.
Node topology — simulated routing
Auto-discovers available local nodes, picks the cheapest one by tier, fails over when a node goes down, and backs off automatically when the media server is already using the GPU.
Python (stdlib only) · MCP · Ollama