https://erwinmongui.com/ Case studies and articles by Erwin Mongui on platform architecture, data, AI and engineering leadership. en Sat, 10 Oct 2026 12:00:00 +0000 https://erwinmongui.com/writing/check-before-you-believe-site-speed/ https://erwinmongui.com/writing/check-before-you-believe-site-speed/ Thu, 08 Oct 2026 12:00:00 +0000 Performance A headless demo against two real Shopify stores, 24 runs under identical conditions: why demos are fast, why one test misleads, and tricks that work. https://erwinmongui.com/writing/seo-geo-aeo-best-practices-log/ https://erwinmongui.com/writing/seo-geo-aeo-best-practices-log/ Thu, 08 Oct 2026 12:00:00 +0000 SEO SEO, GEO and AEO practices expire. A simple system: a dated log, a monthly AI-assisted review with a reusable prompt, and a test before every change. https://erwinmongui.com/writing/bank-marketing-model-threshold-over-model/ https://erwinmongui.com/writing/bank-marketing-model-threshold-over-model/ Sun, 04 Oct 2026 12:00:00 +0000 Data science Revisiting our 2023 Kaggle bank marketing model: seven bugs, a rebuilt pipeline, and why tuning the F1 threshold beat every model change. https://erwinmongui.com/writing/kadabra-movie-recognition-bot-review/ https://erwinmongui.com/writing/kadabra-movie-recognition-bot-review/ Sun, 04 Oct 2026 12:00:00 +0000 Machine learning Revisiting Kadabra, our 2023 Telegram bot that named movies from a photo or a plot: faces, age, vector search, and the evaluation it never had. https://erwinmongui.com/writing/kijiji-car-ads-visit-prediction-rebuild/ https://erwinmongui.com/writing/kijiji-car-ads-visit-prediction-rebuild/ Sun, 04 Oct 2026 12:00:00 +0000 Data science Revisiting our 2023 Kijiji car-ad visit model: a leaked model choice, 51,000 ads squeezed into 190 rows, and a rebuild that beats the baseline by 41%. https://erwinmongui.com/work/fincaraiz-lead-distribution/ https://erwinmongui.com/work/fincaraiz-lead-distribution/ Sat, 26 Sep 2026 12:00:00 +0000 Case study How Erwin Mongui designed Fincaraiz's B2B lead distribution: GraphQL, fault-tolerant retries, 100% data parity and a Connector service for six CRM platforms. https://erwinmongui.com/work/cedar-planters-data-platform/ https://erwinmongui.com/work/cedar-planters-data-platform/ Fri, 25 Sep 2026 12:00:00 +0000 Case study As Cedar Planters' first technical hire, Erwin Mongui replaced third-party reporting tools with one data platform. New reports went from months to hours. https://erwinmongui.com/writing/lead-time-cycle-time-bottlenecks/ https://erwinmongui.com/writing/lead-time-cycle-time-bottlenecks/ Fri, 25 Sep 2026 12:00:00 +0000 Delivery A five-step way to find where software work gets stuck using lead time, cycle time and flow metrics, confirm the cause with the team, and fix it. https://erwinmongui.com/writing/engineering-team-health-metrics/ https://erwinmongui.com/writing/engineering-team-health-metrics/ Thu, 24 Sep 2026 12:00:00 +0000 Leadership The delivery, health and impact metrics I track, how they map to DORA and SPACE, and how to tell whether AI coding assistants are really helping a team. https://erwinmongui.com/work/fincaraiz-monolith-to-microservices/ https://erwinmongui.com/work/fincaraiz-monolith-to-microservices/ Wed, 23 Sep 2026 12:00:00 +0000 Case study How Erwin Mongui moved Fincaraiz from ASP.NET to Django, React and Kubernetes for 5M+ monthly visits: zero downtime, 50% lower costs and NLP search. https://erwinmongui.com/writing/from-data-analyst-to-data-engineer/ https://erwinmongui.com/writing/from-data-analyst-to-data-engineer/ Tue, 22 Sep 2026 12:00:00 +0000 Leadership How asking a data analyst to challenge our pipeline tool led to a better stack and a new data engineer. A guided discovery approach to mentoring, with AI. https://erwinmongui.com/writing/choose-tools-your-team-can-support/ https://erwinmongui.com/writing/choose-tools-your-team-can-support/ Mon, 21 Sep 2026 12:00:00 +0000 Architecture A single sign-on project took six times longer than planned. What went wrong, the tool-selection scorecard we use now, and how AI assistants change it. https://erwinmongui.com/writing/ai-careers-new-graduates/ https://erwinmongui.com/writing/ai-careers-new-graduates/ Tue, 05 Mar 2024 12:00:00 +0000 AI An engineering manager's view of AI careers for new graduates: collaboration, real projects, AI-assisted development, evaluation, ethics and frameworks. https://erwinmongui.com/writing/ai-applications-json/ https://erwinmongui.com/writing/ai-applications-json/ Tue, 06 Feb 2024 12:00:00 +0000 AI Why JSON became the contract between software and AI models: structured outputs with JSON Schema and Pydantic, tool calling, MCP, memory and model configs. https://erwinmongui.com/writing/rt-pcr-travel-screening-data-driven-selection/ https://erwinmongui.com/writing/rt-pcr-travel-screening-data-driven-selection/ Tue, 12 Dec 2023 12:00:00 +0000 Research Our STEM Fellowship Big Data and AI Challenge 2023 paper: using WHO and Government of Canada data to prioritize travellers for RT-PCR checks, not at random.