I woke up to a $12,450 usage bill this morning.

I woke up to a $12,450 usage bill this morning. Happy Monday. My first thought: the AI went off the rails. I must have forgot to set a spending limit. Must have run some infinite loop while I was sleeping. Credits burned. Budget destroyed.

Nope. It wasn't AI credits at all.

It was a missing rate limit. Users hit an endpoint with no throttle, and the system kept creating accounts, unchecked, unlimited, all night long.

$12k+ in Auth, compute and database charges. Not from AI. From a missing if statement. Time to spin up AI agent to negotiate refunds....

Here's the thing, this is going to become more common, not less.

We're in an era where you can build and ship an entire product in a weekend with Claude Code. I've done it. It's incredible. But speed creates blind spots.

When you're moving fast with AI-assisted development:

You ship faster than you secure. The feature works, the demo looks great, the app is live but did you add rate limiting? Auth checks? Input validation? Usage caps?

You trust the happy path. AI helps you build the thing that works. It doesn't always remind you to build the thing that prevents abuse.

Your bill is the error message. In the old days, you'd find bugs in QA. Now you find them in your billing dashboard on Monday morning.

Lessons learned: - Rate limit everything. Every endpoint. Every user action. Day one. - Set billing alerts at thresholds that make you uncomfortable, not just the max. - Build the guardrails before you build the features. - AI agent to negotiate refunds

#AI #ClaudeCode #BuildInPublic #Startups #CyberSecurity #RateLimiting #LessonsLearned #AIWrangler