Case: staged regional rollout caught a template bug before it hit 50,000 pages

Case: staged regional rollout caught a template bug before it hit 50,000 pages

New '{City} {Service}' template, 50,000 cities queued. Instead of bulk publish:

— Step 1 (ops): shipped a 500-city pilot in one region only. Gate: pilot must run 14 days before scale-up.
— Step 2 (QA): at day 7, audited the pilot. Found the population data field defaulted to '0' for 18% of cities, printing 'population of 0' on-page.
— Step 3 (dev): added a null-guard, hiding the population line when data was missing. Gate: no field renders a default placeholder.
— Step 4 (ops): re-piloted, then scaled in 800/day batches.

Outcome: the bug that would have shipped to ~9,000 pages was caught at 90. Full 50k rollout completed clean, 91% indexation.

Guardrail: always pilot one segment; a template bug multiplies by your page count.

Ship gate: don't publish until all boxes are checked.