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

# Client Signing

The client does not prepare wallet operations. It only signs prepared
transactions.

## What to look for

If a prepared transaction has `signatureRequests.length > 0`, the client still
needs to sign it before submission.

## Ed25519 signing

For normal Solana-key signing, use `signPreparedTransaction(...)`:

```typescript theme={null}
import {
  signPreparedTransaction,
  type PreparedTransaction,
} from '@swig-wallet/developer-sdk/client';
import { VersionedTransaction } from '@solana/web3.js';

declare const prepared: PreparedTransaction;

const signed = await signPreparedTransaction(prepared, {
  signTransaction: async (transaction) => {
    const versioned = VersionedTransaction.deserialize(
      Buffer.from(transaction, 'base64'),
    );
    versioned.sign([userKeypair]);
    return Buffer.from(versioned.serialize()).toString('base64');
  },
});
```

## Secp256r1 and passkeys

For passkey-backed prepared transactions, use the Swig signing helpers:

```typescript theme={null}
import {
  createSecp256r1PasskeySigningFn,
  signPreparedSwigTransaction,
} from '@swig-wallet/developer-sdk/client';

const passkeySigningFn = createSecp256r1PasskeySigningFn({
  allowCredentials: [{ id: credentialId, type: 'public-key' }],
  userVerification: 'preferred',
});

const signed = await signPreparedSwigTransaction(prepared, {
  secp256r1: passkeySigningFn,
});
```

## Secp256k1 and EVM wallets

For EVM-backed prepared transactions, use the EVM helper. It wraps an EIP-1193
provider with `personal_sign` and adds the Ethereum message prefix expected by
Swig's `secp256k1` authority payload.

```typescript theme={null}
import {
  createSecp256k1EvmSigningFn,
  signPreparedSwigTransaction,
  type PreparedTransaction,
} from '@swig-wallet/developer-sdk/client';

declare const prepared: PreparedTransaction;
declare const evmAddress: string;

const evmSigningFn = createSecp256k1EvmSigningFn({
  provider: window.ethereum,
  address: evmAddress,
});

const signed = await signPreparedSwigTransaction(prepared, {
  secp256k1: evmSigningFn,
});
```

## After signing

Once the client has signed the required transactions, your app can send them
directly or hand them to [Sponsor & Submit](/developer-sdk/sponsor-and-submit).