Articles, talks and architecture katas by Ahmet Kalafat on data platforms, AI governance and data for AI.https://ahmetkalafat.com/enhttps://ahmetkalafat.com/publications/wrong-data-costs-more-than-missing-data/https://ahmetkalafat.com/publications/wrong-data-costs-more-than-missing-data/How I built two-stage validation into a GenAI-assisted data pipeline, and why I didn't give the model the final say.Sun, 18 Oct 2026 00:00:00 GMTBloghttps://ahmetkalafat.com/publications/twelve-techniques-one-scorecard/https://ahmetkalafat.com/publications/twelve-techniques-one-scorecard/What I measured while testing a GenAI data pipeline, what the first run found, and what I fixed.Sun, 18 Oct 2026 00:00:00 GMTBloghttps://ahmetkalafat.com/publications/why-i-lowered-my-own-maturity-score/https://ahmetkalafat.com/publications/why-i-lowered-my-own-maturity-score/On measuring the ability to measure, and staying honest with my own scorecard: how a maturity score went from 37.9% to 89.7% and why I lowered it to 84.5%.Sun, 18 Oct 2026 00:00:00 GMTBloghttps://ahmetkalafat.com/publications/data-warehouse-platform-selection/https://ahmetkalafat.com/publications/data-warehouse-platform-selection/Start a data warehouse migration with pain points, not products: a two-week PoC, a three-year TCO and a signed plan to close the old system.Wed, 14 Oct 2026 06:59:50 GMTBloghttps://ahmetkalafat.com/publications/genai-governance-production/https://ahmetkalafat.com/publications/genai-governance-production/Governance for GenAI beyond the demo: a use-case card, field-level evals, robustness tests, a release gate with replay, drift tracking and a kill switch.Wed, 14 Oct 2026 00:00:00 GMTBloghttps://ahmetkalafat.com/publications/kata-dwh-migration-bigquery/https://ahmetkalafat.com/publications/kata-dwh-migration-bigquery/A fictional architecture kata: migrating a 60 TB SQL Server warehouse to BigQuery table by table, with dual-run, hash reconciliation and capped cost.Wed, 14 Oct 2026 00:00:00 GMTBloghttps://ahmetkalafat.com/katas/cold-chain-telemetry-compliance-platform/https://ahmetkalafat.com/katas/cold-chain-telemetry-compliance-platform/20,000 refrigerated vehicles, 72-hour offline gaps, and GDP reports that an auditor can verify instead of having to trust.Wed, 14 Oct 2026 00:00:00 GMTArchitecture katahttps://ahmetkalafat.com/katas/open-lakehouse-data-contracts/https://ahmetkalafat.com/katas/open-lakehouse-data-contracts/Six brands keep their query engines, shared data is written once as an open table, guarded by a contract in CI and one metric definition.Wed, 14 Oct 2026 00:00:00 GMTArchitecture katahttps://ahmetkalafat.com/katas/regional-health-information-exchange/https://ahmetkalafat.com/katas/regional-health-information-exchange/Eight EHR systems into one FHIR record per patient, reversible patient matching, consent on every read, ten-year audit trail.Wed, 14 Oct 2026 00:00:00 GMTArchitecture katahttps://ahmetkalafat.com/katas/dwh-migration-to-bigquery/https://ahmetkalafat.com/katas/dwh-migration-to-bigquery/Move a 60 TB SQL Server warehouse and 1,900 ETL packages to BigQuery in 12 months, wave by wave, with every table reconciled.Wed, 14 Oct 2026 00:00:00 GMTArchitecture katahttps://ahmetkalafat.com/katas/instant-payment-fraud-decisioning/https://ahmetkalafat.com/katas/instant-payment-fraud-decisioning/Score every instant payment for fraud in 150 ms, keep each decision reproducible for seven years, touch the mainframe only through MQ.Wed, 14 Oct 2026 00:00:00 GMTArchitecture katahttps://ahmetkalafat.com/katas/telecom-bss-modernization-customer-360/https://ahmetkalafat.com/katas/telecom-bss-modernization-customer-360/Build a Customer 360 from change events of 14 systems without touching the mainframe, then retire billing by cohort over five years.Wed, 14 Oct 2026 00:00:00 GMTArchitecture katahttps://ahmetkalafat.com/katas/unified-marketing-intelligence/https://ahmetkalafat.com/katas/unified-marketing-intelligence/One certified metric layer over a GA4 stream, four batch sources and the warehouse, so dashboards, an LLM and agents quote one number.Wed, 14 Oct 2026 00:00:00 GMTArchitecture katahttps://ahmetkalafat.com/katas/competitor-price-markdown-intelligence/https://ahmetkalafat.com/katas/competitor-price-markdown-intelligence/Collect competitor pages within legal limits, match them to 120,000 SKUs with measured precision, advise on markdown timing with evidence.Wed, 14 Oct 2026 00:00:00 GMTArchitecture katahttps://ahmetkalafat.com/katas/governed-genai-data-agents/https://ahmetkalafat.com/katas/governed-genai-data-agents/Three enterprise agents limited to certified metrics, contracted data and permitted documents, with traced answers and gated releases.Wed, 14 Oct 2026 00:00:00 GMTArchitecture katahttps://ahmetkalafat.com/katas/insurance-claims-document-intelligence/https://ahmetkalafat.com/katas/insurance-claims-document-intelligence/Self-hosted models recommend, rules and adjusters decide, eight GPUs sit behind a queue, every decision is auditable for seven years.Wed, 14 Oct 2026 00:00:00 GMTArchitecture katahttps://ahmetkalafat.com/publications/who-audits-ai-decisions/https://ahmetkalafat.com/publications/who-audits-ai-decisions/On AI accountability: who audits an AI decision, and the case for AI ethics boards organised by sector.Fri, 02 Oct 2026 00:00:00 GMTBloghttps://ahmetkalafat.com/publications/will-ai-eliminate-jobs/https://ahmetkalafat.com/publications/will-ai-eliminate-jobs/AI rarely erases jobs; it breaks them into tasks and redesigns them. What ILO data, Klarna and Verizon reveal about data, process and junior roles.Fri, 04 Sep 2026 05:33:00 GMTBloghttps://ahmetkalafat.com/publications/data-security-in-the-copy-paste-age/https://ahmetkalafat.com/publications/data-security-in-the-copy-paste-age/Most AI data leaks start with a well-meaning copy-paste, not a hacker. Shadow AI, personal accounts, KVKK guidance, and how to design for safe use.Thu, 03 Sep 2026 05:19:00 GMTBloghttps://ahmetkalafat.com/publications/hidden-bill-of-ai-vendor-lock-in/https://ahmetkalafat.com/publications/hidden-bill-of-ai-vendor-lock-in/AI pilots look cheap; production does not. How model retirements, usage growth, unready data and exit costs add up to a hidden bill, and what to do.Thu, 03 Sep 2026 05:17:00 GMTBloghttps://ahmetkalafat.com/publications/ai-ethics-is-not-a-compliance-checkbox/https://ahmetkalafat.com/publications/ai-ethics-is-not-a-compliance-checkbox/An AI ethics policy is not control. Who chose the model, who monitors it, and who pulls it when it fails? Why ethics now belongs in the architecture.Tue, 01 Sep 2026 21:29:00 GMTBloghttps://ahmetkalafat.com/publications/ai-speed-or-identity/https://ahmetkalafat.com/publications/ai-speed-or-identity/Why the real AI question for organizations is control, not speed: the introduction to the series and the three questions behind every AI decision.Tue, 01 Sep 2026 21:28:00 GMTBloghttps://ahmetkalafat.com/publications/#sql-saturday-istanbul-2014https://ahmetkalafat.com/publications/#sql-saturday-istanbul-2014Wed, 01 Jan 2014 00:00:00 GMTTalk