How I Built a Flat-Rate Reverse Geocoding API for Japan to Escape Google Maps Bill Shock

If you've ever built a global app or travel tool operating in Japan, you know the struggle:

Google Maps Geocoding API pricing: At $5.00 per 1,000 requests, unexpected traffic spikes can lead to terrifying monthly bills.

Messy Japanese address data: Official Japanese government (MLIT) CSVs and Japan Post files are difficult to normalize and query without self-hosting a spatial database like PostGIS.

To solve this for indie hackers and global dev teams, I built ReverseGeoJP — a fast, flat-rate reverse geocoding API for Japan address data.

What it does