# 02 — What's a nano?

Part 2 of 7 · ← Where to start · Index · Next → A nano in insurance

A nano is a small app living inside ChatGPT.

When a user types something your nano handles, ChatGPT opens a panel right there in the conversation — your UI, your data, your shape.

Three real examples

• Figma — "turn this sketch into a diagram" → Figma panel with the diagram.
• Zillow — "3-bedroom in Austin under $500k" → map + listings inside the chat.
• Spotify — "make me a focus playlist" → player inside the chat.

Who does what?

Think restaurant:

• User = customer. Asks in plain words.
• ChatGPT = waiter. Understands the order, routes it to the right kitchen.
• Your nano = kitchen. Two parts:
• A brain — a small server online. Does the work.
• A face — a visible panel. Shows buttons and data.

You build both parts of the kitchen. ChatGPT handles everything else.