SOP: Pick your geo source — IP database vs edge header

SOP: Pick your geo source — IP database vs edge header

Two ways to read a click's country. They disagree more than you'd think.

Step 1 — Audit your current source. Most self-hosted routers use a static MaxMind GeoLite2 file. CDN-fronted setups expose a country header (CF-IPCountry, x-vercel-ip-country).
Step 2 — Compare accuracy. Static databases drift; refresh monthly or your mobile-carrier IPs misfire by 3-8%.
Step 3 — Choose by stack.
☐ On a CDN already → use the edge header, zero lookup latency
☐ Self-hosted, no CDN → MaxMind file, cron a monthly update
☐ High-value geos (Tier-1 gambling) → query a paid live API only on those, cache 24h
Step 4 — Never mix two sources in one campaign. Pick one, log it, so QA can reproduce a misroute.

Repeat the database refresh monthly; re-audit the source choice each quarter.