Troubleshooting & Pitfalls

Currency Handling Mistakes

❌ Forgetting Cents Conversion

// WRONG
const withdrawAmount = request.amount; // 5000 treated as $5000

// CORRECT
const withdrawAmount = request.amount / 100; // 5000 cents = $50

❌ Using Floating-Point Arithmetic

// WRONG
const newBalance = balance - (amount * 0.01);

// CORRECT
const newBalance = (balanceInCents - amountInCents) / 100;

Security Mistakes

❌ Skipping Signature Verification

• Always verify signatures, even in dev/staging
• Use proper RSA verification with SHA-256
• Never trust requests without valid signatures

❌ Logging Sensitive Data

// WRONG
console.log('Request:', { ...request, signature });

// CORRECT
console.log('Request:', { ...request, signature: '[REDACTED]' });

Performance Issues

❌ Making Blocking External Calls

// WRONG
const externalData = await slowExternalAPI.getData();

// CORRECT
const result = processWithdraw(cachedData);
// Update cache asynchronously

❌ Synchronous Operations

• Use async logging libraries
• Implement non-blocking database queries
• Avoid synchronous file operations

Data Integrity Issues

❌ Not Handling Race Conditions

• Use database transactions with proper isolation
• Implement row-level locking (SELECT FOR UPDATE)
• Queue requests per player if needed

❌ Ignoring Idempotency

• Always check tx_id before processing
• Store and return previous responses for duplicates
• Handle retries gracefully

❌ Missing Rollback Logic

• Wrap operations in transactions
• Implement compensating transactions for failures
• Test rollback scenarios thoroughly

Debugging Strategies

Common Issues

• Timeout errors: Check database query performance and indexes
• Balance discrepancies: Verify transaction atomicity and rollback logic
• Signature failures: Validate key format and signing process
• Race conditions: Review concurrent request handling

Circuit Breaker Implementation

• Monitor failure rates for external dependencies
• Open circuit after threshold failures
• Provide fallback responses during outages
• Automatically retry after cooldown period