Just like cryptocurrency, fiat e-wallets must prevent the same funds from being used twice. This requires for every transaction request.
def pay(self, amount, recipient_wallet): if amount <= 0: return "Amount must be positive" if self.balance < amount: return "Insufficient balance"
try: # 1. Lock the sender's wallet row to prevent other writes (Pessimistic Locking) sender = SELECT * FROM wallets WHERE id = sender_wallet_id FOR UPDATE; e wallet code
Imagine two API calls trying to deduct from the same balance at the same time. Without proper locking or database transactions, users could overspend.
Developers must integrate AML (Anti-Money Laundering) and KYC (Know Your Customer) protocols to meet global financial regulations. 3. Security and Risk Management Just like cryptocurrency, fiat e-wallets must prevent the
except Exception as e: # If anything fails, roll back everything rollback_transaction() raise e
Depending on the context, an e-wallet code serves different purposes: E-wallet: Definition and advantages - E-Pay Space Lock the sender's wallet row to prevent other
To solve this, developers use or Pessimistic Locking .
In this post, I’ll walk you through the , the security challenges, and a simple code example to show how a basic digital wallet might work.
✅ Use atomic database operations or optimistic locking (e.g., UPDATE wallets SET balance = balance - 10 WHERE user_id = X AND balance >= 10 ).