What Are API Keys? Why They're Valuable and Why People Steal Them

If you've built anything with AI tools, you've probably encountered API keys. Stripe needs one. OpenAI needs one. Supabase gives you two. They're everywhere, and your AI assistant probably told you to "put them in your .env file."

But what actually are they? Why do services use them? And why is it such a big deal if someone gets hold of yours?

API Keys in Plain English

An API key is like a password that identifies your application to a service. When you sign up for Stripe, they give you a key that says "this request is coming from Alex's app." Every time your app talks to Stripe, it includes that key so Stripe knows who's making the request.

Think of it like a membership card at a warehouse store. You flash your card to get in. The store knows who you are, tracks your purchases, an