# Add networks in AppKit (https://docs-rbcpr9qys-ton-core-docs.vercel.app/llms/applications/appkit/get-started/networks/content.md)



Declare every chain the app can read. A network in AppKit is the chain context AppKit uses to read data and to compare wallet state against the app's expected chain — each network is identified by a `Network` value with a `chainId` and carries an `apiClient` that reads chain state for that chain.

A single `AppKit` instance can hold more than one network. The user picks at connect time, and a flow can move between networks without rebuilding the instance.

## Before you begin [#before-you-begin]

Install AppKit first. See [Prepare your project](https://docs-rbcpr9qys-ton-core-docs.vercel.app/llms/applications/appkit/get-started/installation/installation/content.md).

## Basic configuration [#basic-configuration]

By default, AppKit constructs a mainnet-only `ApiClientToncenter` with no API key when `networks` is omitted. That is enough to start exploring AppKit, but production traffic will hit TON Center's public rate limits — apps that ship to users should supply their own key.

Pass an `apiClient` entry on the network with a `key` to lift the limits. AppKit has preset URLs for mainnet (`https://toncenter.com`) and testnet (`https://testnet.toncenter.com`), so `url` can be omitted for those. For other networks, specify `url` explicitly.

```ts
const appKit = new AppKit({
  networks: {
    [Network.mainnet().chainId]: {
      apiClient: {
        key: 'your-key',
      },
    },
  },
});
```

## Next steps [#next-steps]

* Continue to [Use basic getter hooks](https://docs-rbcpr9qys-ton-core-docs.vercel.app/llms/applications/appkit/get-started/basic-getter-hooks/content.md) to read the connected wallet's state from the configured networks.
* For multiple networks, custom chains, the default network, and mismatch handling, see [Configure networks](https://docs-rbcpr9qys-ton-core-docs.vercel.app/llms/applications/appkit/howto/networks/content.md).