Videos
Build walkthroughs
Every video has a written version on this site with the code, the diagrams and the parts that are hard to follow on screen.
24:22
Building a RAG Evaluation Harness From Scratch
Why retrieval and generation must be measured separately, and how to build the harness that does it.
18K views25 Aug 2026
Written version
30:40
Why Most Backtests Lie
Five structural biases that make trading strategies look better than they are.
31K views20 Aug 2026
Written version
22:05
Making Power BI Fast on 40 Million Rows
Aggregations, relationship configuration and the DAX rewrites that took a page from 8.4s to 0.6s.
24K views9 Aug 2026
Written version
35:12
The Entire Modern Data Stack, On a Laptop
DuckDB, dbt and Dagster — every concept a cloud stack teaches, without the bill.
43K views13 Jul 2026
Written version