# Start chatting

> Sign up, chat on your signup credit, and set up a wallet if you want to pay in USDC.

Section: Start. Web page: https://docs.katara.com/start/chat/

Katara's chat app runs in the browser. Sign-in is an email and password. Each reply is paid with account credits or with USDC from a wallet you control; a new account starts on credits.

The chat app is at `https://chat.katara.com`, and the account, billing, wallet and API keys live in the portal at `https://platform.katara.com`; both share one sign-in. Chat pays from Live, on Avalanche C-Chain. The [API](https://docs.katara.com/start/api.txt) can also run in Test; [Networks](https://docs.katara.com/about/networks.txt) explains the two.

## 1. Sign up

Open the chat app, choose **Create account**, and confirm your email. Your account then receives a signup credit, which pays for your first replies. It is spent before any credits you buy and expires 90 days after it is granted.

## 2. Choose how to pay

The balance in the header is what pays for your next message. Click it to switch between **Credits** and **USDC**. With credits you can chat straight away; buy more by card under **Billing** in the portal. Replies paid either way can run on Katara Community while it is on.

To pay with USDC instead, set up a wallet (steps 3 to 5). Replies paid with USDC can also run on independent providers in Katara Community, unless you turn it off. With it on, Community providers are tried first, and their replies may take longer to start.

## 3. Create your wallet

Open **Account → Wallet** in settings and choose **Create wallet**. Your browser asks for a passkey (Touch ID, Windows Hello, a security key). That passkey is the only thing that can sign for the wallet. Katara never has its keys.

You will see an address. That is where USDC lives.

## 4. Add funds

Send USDC on Avalanche C-Chain to your address from any wallet or exchange.

## 5. Approve spending

Paying with USDC is paused until you approve spending. The **Approve spending** button asks for one passkey signature and lets Katara pull the exact cost of each reply from your balance, up to your budget, for the period you pick (30 days, 6 months, or a year). You can withdraw the approval at any time.

By default the budget follows your balance. Set a cap in the same panel if you want a hard limit.

## 6. Chat

Pick a model in the header and send a message. Under each reply you see its cost, in Credits or USDC. The balance in the header updates after every reply.

The chat app asks Katara Cortex by default, so if the provider that was serving you goes away mid-conversation, the next reply comes from another model and says which one. See [Katara Cortex](https://docs.katara.com/concepts/cortex.txt).