race condition fixed, payment inside

README.md

@@ -37,7 +37,16 @@ NOWPAYMENTS_CURRENCY=usd  # Sandbox doesn't support CHF, use USD or other suppor
 # IPN Callback URL (your external Node.js service that handles IPN callbacks)
 IPN_CALLBACK_URL=http://your-ipn-service.com/api/payments/ipn-callback
 
-# Base URL for success/cancel redirects (use your domain in production)
+# Payment Currency (crypto currency for payments, e.g. btc, eth, usdt)
+# Default: btc
+NOWPAYMENTS_PAY_CURRENCY=btc
+
+# Use Fixed Rate (optional, true/false)
+# If true, exchange rate is frozen for 20 minutes. Payment expires if not paid within 20 minutes.
+# Default: false
+NOWPAYMENTS_FIXED_RATE=false
+
+# Base URL (use your domain in production)
 NEXT_PUBLIC_BASE_URL=http://localhost:3420
 ```