Most apps using country / state / city data cache it locally for performance. The downside: when a country splits, an ISO code changes, or a state gets renamed, your cache goes stale until the next manual refresh. ApogeoAPI's webhook system pushes those events to your endpoint as soon as the underlying data changes. This tutorial covers the full setup with HMAC signature verification. Available events Event Fired when country.created A new country is added to the database (rare — average ~1/year) country.updated Any field on a country changes (capital, currency, name, region) country.deleted A country is removed (extremely rare) state.updated A state/province record changes currency_rate.updated Live FX refresh — fires every 4 hours per currency Register the webhook From your dashboard at app.apogeoapi.com → Webhooks → Add endpoint. Paste your URL, choose which events to subscribe to, and copy the secret.…