A country in Coin Heaven is one small file in the regions/ folder. No programming is needed beyond editing numbers.

• The currency and how numbers and dates are written
• Tax brackets for investment withdrawals, written as plain percentages
• Retirement defaults (pension age, safe withdrawal rate)
• Property purchase-tax defaults
• The words your bank puts on statements that mean nothing ("card payment at", "purchase with card"), so merchants are recognised cleanly

1. Copy regions/us.json to regions/<your-country>.json.
2. Change the values. Percentages are percentages; amounts are whole units.
3. Run pnpm check:regions. It tells you exactly what is wrong.
4. Open the app: your country appears in Settings and in the FIRE tax section.
5. Send it as a pull request. Please say where the numbers come from (a tax authority page is ideal), and what year they are for.

The file format is explained in regions/README.md.

Screens are translated with one folder of small text files per language in src/locales/. Copy the English folder, translate the sentences, and the app picks it up. A natural translation beats a literal one: keep English words where people in your country really use them (cash flow, FIRE).