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

# Write Contract

> Call state-changing functions on smart contracts

## Method Signature

```typescript theme={null}
align.blockchain.contracts.write(
  params: ContractTransaction
): Promise<TransactionResponse>
```

## Parameters

<ParamField body="contractAddress" type="string" required>
  Contract address
</ParamField>

<ParamField body="abi" type="array" required>
  Contract ABI
</ParamField>

<ParamField body="method" type="string" required>
  Function name to call
</ParamField>

<ParamField body="args" type="array">
  Function arguments
</ParamField>

<ParamField body="wallet" type="Wallet" required>
  Wallet for signing
</ParamField>

<ParamField body="network" type="string" required>
  Target network
</ParamField>

## Returns

Returns an ethers.js `TransactionResponse` that can be awaited for confirmation.

## Examples

<Tabs>
  <Tab title="TypeScript">
    ```typescript theme={null}
    import Align from "@tolbel/align";

    const align = new Align({
      apiKey: process.env.ALIGN_API_KEY!,
      environment: "sandbox",
    });

    const wallet = await align.blockchain.wallets.createFromPrivateKey(
      process.env.PRIVATE_KEY!
    );

    // Approve USDC spending
    const ERC20_ABI = [
      "function approve(address spender, uint256 amount) returns (bool)",
    ];

    const tx = await align.blockchain.contracts.write({
      contractAddress: "0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174",
      abi: ERC20_ABI,
      method: "approve",
      args: ["0xSpenderAddress...", "1000000000"], // 1000 USDC
      wallet,
      network: "polygon",
    });

    console.log(`TX Hash: ${tx.hash}`);

    // Wait for confirmation
    const receipt = await tx.wait();
    console.log(`Confirmed in block ${receipt?.blockNumber}`);
    ```
  </Tab>

  <Tab title="JavaScript">
    ```javascript theme={null}
    const tx = await align.blockchain.contracts.write({
      contractAddress: tokenAddress,
      abi: ERC20_ABI,
      method: "approve",
      args: [spender, amount],
      wallet,
      network: "polygon",
    });

    await tx.wait();
    console.log("Approved!");
    ```
  </Tab>
</Tabs>

### ERC-20 Transfer

```typescript theme={null}
const tx = await align.blockchain.contracts.write({
  contractAddress: USDC_ADDRESS,
  abi: ["function transfer(address to, uint256 amount) returns (bool)"],
  method: "transfer",
  args: [recipientAddress, "50000000"], // 50 USDC
  wallet,
  network: "polygon",
});

const receipt = await tx.wait();
console.log(`Transferred in block ${receipt?.blockNumber}`);
```

<Warning>
  Write operations require native tokens for gas. Ensure the wallet has
  sufficient balance.
</Warning>

## Related Methods

<CardGroup cols={2}>
  <Card title="Read Contract" icon="file-lines" href="/docs/api/blockchain/contracts/read">
    Call view functions
  </Card>

  <Card title="Get Events" icon="list" href="/docs/api/blockchain/contracts/get-events">
    Query contract events
  </Card>
</CardGroup>