# Chains

The following Tempo chains are available:

```ts
import { Chain } from 'viem/tempo'

Chain.mainnet // [!code hl]
Chain.testnet // [!code hl]
Chain.devnet // [!code hl]
Chain.localnet // [!code hl]
Chain.moderato // [!code hl]
```

You can also import Tempo chains by name from `viem/tempo/chains`:

```ts
import {
  tempo, // [!code hl]
  tempoMainnet, // [!code hl]
  tempoDevnet, // [!code hl]
  tempoLocalnet, // [!code hl]
  tempoModerato, // [!code hl]
  tempoTestnet, // [!code hl]
} from 'viem/tempo/chains'
```

Tempo chains are still exported from `viem/chains` if you prefer to import them from the shared chains entrypoint:

```ts
import { tempo, tempoModerato } from 'viem/chains'
```

## Default Fee Token

It is possible to set a default fee token for a Tempo chain by adding a `feeToken` property as an extension to the chain.

Once set, all transactions will use this token as the default fee token, unless an override is provided at the transaction level.

```ts
import { Chain } from 'viem/tempo'

const chain = Chain.testnet.extend({
  feeToken: '0x20c0000000000000000000000000000000000001',
})
```