Back to Code | Ep 06: State Hell and Idempotency

The 15-week technical battle of LogiFlow — a company waking up from the illusion created by artificial intelligence and returning to real engineering.

The Story

A network fluctuation hit the payment gateway. The system received a "Timeout" and retried the operation. The customer's card was charged twice. AI, when writing HTTP requests, had no concept of "Idempotency."

The customer support team noticed it first. Then the finance team. Then legal. A single network hiccup had turned into a compliance incident, and the root cause was embarrassingly simple: the retry logic had no deduplication mechanism.

Technical Autopsy: AI Only Sees the Happy Path

// Dangerous: No idempotency
async function chargeCustomer(
  orderId: string, amount: number
) {
  await stripe.charges.create({
    amount, currency: 'usd'
  });
}

In AI's world, networks are reliable. Requests always succeed on the first try. Timeouts don't exist. And if they do, you just retry — what could go wrong?

Everything. Everything could go wrong.

When the payment gateway timed out, the charge had actually succeeded on Stripe's side. The timeout was on the response, not the request. The retry created a second, duplicate charge.

The Human Fix: Managing Distributed Chaos

// Safe: With idempotency key
async function chargeCustomer(
  orderId: string,
  amount: number,
  idempotencyKey: string
) {
  // Retries with the same key are rejected
  await stripe.charges.create(
    { amount, currency: 'usd' },
    { idempotencyKey }
  );
}

Fallacies of Distributed Computing: The network is unreliable. It delays, disconnects, sends duplicate packets. Async operations written without idempotency keys are financial disasters.