> ## Documentation Index
> Fetch the complete documentation index at: https://stablelabs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Use the SDK with viem

> Sign with @stablechain/sdk three ways: a private-key Account, a browser Transport, or a pre-built viem WalletClient.

`@stablechain/sdk` is built on viem. `createStable` accepts three signing modes, and you pick one based on where the code runs: server-side with a private key, browser-side with the user's wallet, or with a `WalletClient` you've already constructed (for example, in a wagmi app).

This guide shows each mode end-to-end.

## Server-side: private-key `Account`

Use `privateKeyToAccount` from viem to sign with a private key held by your backend.

```ts theme={"dark"}
import "dotenv/config";
import { createStable, Network } from "@stablechain/sdk";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`);

const stable = createStable({
  network: Network.Mainnet,
  account,
});

const { txHash } = await stable.transfer({
  from: account.address,
  to: "0xRecipient",
  amount: 5,
});

console.log(txHash);
```

```text theme={"dark"}
0x8f3a...2d41
```

## Browser-side: `Transport` from a wallet

Pass `custom(window.ethereum)` (or any EIP-1193 provider) as `transport`. The SDK builds the `WalletClient` and reads the signer address from the provider.

```ts theme={"dark"}
import { createStable, Network } from "@stablechain/sdk";
import { custom } from "viem";

const stable = createStable({
  network: Network.Mainnet,
  transport: custom(window.ethereum),
});

const [from] = await window.ethereum.request({ method: "eth_requestAccounts" });

const { txHash } = await stable.transfer({
  from,
  to: "0xRecipient",
  amount: 5,
});
```

```text theme={"dark"}
0x8f3a...2d41
```

<Warning>
  `transfer`, `bridge`, and `swap` call `switchChain` to put the wallet on the right network. If the user rejects, the SDK throws `StableTransactionError` with `phase: "switch_chain"`. Catch it and surface a retry to the user.
</Warning>

## Bring your own `WalletClient`

When you already have a `WalletClient` (for example, from wagmi or a custom signer), pass it directly. It takes precedence over `account` and `transport`.

```ts theme={"dark"}
import { createStable, Network } from "@stablechain/sdk";
import { createWalletClient, custom } from "viem";
import { stable as stableChain } from "viem/chains";

const walletClient = createWalletClient({
  chain: stableChain,
  transport: custom(window.ethereum),
});

const [from] = await walletClient.requestAddresses();

const stable = createStable({
  network: Network.Mainnet,
  walletClient,
});

const { txHash } = await stable.transfer({ from, to: "0xRecipient", amount: 5 });
```

```text theme={"dark"}
0x8f3a...2d41
```

## Pick a mode

| **Mode**       | **Use when**                                                                  |
| :------------- | :---------------------------------------------------------------------------- |
| `account`      | Backend services, scripts, agents — anywhere you hold the key.                |
| `transport`    | Browser apps where the user signs with MetaMask or a wagmi-less custom flow.  |
| `walletClient` | You already have a configured `WalletClient` (wagmi, RainbowKit, ConnectKit). |

## Next recommended

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