# Reference: `sushi` Chain

Root chain exports provide a unified registry across EVM, SVM, MVM, and Stellar.

| Export | Purpose |
|---|---|
| `chains` | All known chains. |
| `ChainId` | Enum-like lookup from uppercase chain keys to chain IDs. |
| `chainIds` | Known chain ID array. |
| `isChainId` | Type guard for unknown numbers. |
| `getChainById` | Lookup by chain ID. |
| `MainnetChainId`, `isMainnetChainId` | Mainnet type and guard. |
| `TestnetChainId`, `isTestnetChainId` | Testnet type and guard. |
| `ChainKey`, `isChainKey`, `getChainByKey` | Chain key type, guard, and lookup. |

`ChainId` converts uppercase property names to chain keys. For example, `ChainId.ETHEREUM` resolves the chain with key `ethereum`.

```ts twoslash
import { ChainId, chains, getChainById, getChainByKey, isChainId } from 'sushi'

const ethereum = getChainById(ChainId.ETHEREUM)
const base = getChainByKey('base')

for (const chain of chains) {
  console.log(chain.name)
}

if (isChainId(1)) {
  getChainById(1)
}
```