dataSuffix - Base Documentation

Defined in ERC-8021

The dataSuffix capability allows apps to append arbitrary hex-encoded bytes to transaction calldata. This enables attribution tracking, allowing platforms to identify which app originated a transaction and distribute rewards accordingly.

Parameters

value

`0x${string}`

required

Hex-encoded bytes to append to the transaction calldata. This value is appended to the end of the calldata for each call in the batch.

optional

boolean

When true, the wallet may ignore the capability if it doesn’t support it. When false or omitted, the wallet must support the capability or reject the request.

Returns

dataSuffix

object

The data suffix capability configuration for the specified chain.

Show DataSuffix capability properties

supported

boolean

Indicates whether the wallet supports appending data suffixes to transaction calldata.

Example Usage

const capabilities = await provider.request({
  method: 'wallet_getCapabilities',
  params: [userAddress]
});

const dataSuffixSupport = capabilities["0x2105"]?.dataSuffix;

const result = await provider.request({
  method: "wallet_sendCalls",
  params: [{
    version: "1.0",
    chainId: "0x2105",
    from: userAddress,
    calls: [{
      to: "0x1234567890123456789012345678901234567890",
      value: "0x0",
      data: "0xa9059cbb000000000000000000000000..."
    }],
    capabilities: {
      dataSuffix: {
        value: "0x1234567890abcdef1234567890abcdef",
        optional: true
      }
    }
  }]
});

{
  "0x2105": {
    "dataSuffix": {
      "supported": true
    }
  }
}

{
  "0x2105": {
    "dataSuffix": {
      "supported": false
    }
  }
}

Error Handling

Code	Message	Description
4100	Data suffix not supported	Wallet does not support data suffix functionality
5700	DataSuffix capability required	Transaction requires dataSuffix but wallet doesn’t support it

How It Works

When a wallet receives a dataSuffix capability, the suffix is appended to userOp.callData. The suffix bytes are concatenated directly to the end of the calldata, making them available for onchain parsing and attribution.

Use Cases

Builder Codes Attribution

The primary use case for dataSuffix is Builder Codes attribution. Builder Codes are unique identifiers that allow apps to receive attribution for onchain activity they generate.

import { Attribution } from "ox/erc8021";

// Example: Using Builder Code with dataSuffix.
// Using the ox/erc8021 package to generate the ERC-8021 suffix from your builder code.
const builderCodeSuffix = Attribution.toDataSuffix({
  codes: ['bc_foobar'], // Get your code from base.dev
});

await provider.request({
  method: "wallet_sendCalls",
  params: [{
    version: "1.0",
    chainId: "0x2105",
    from: userAddress,
    calls: [{
      to: contractAddress,
      value: "0x0",
      data: swapCallData
    }],
    capabilities: {
      dataSuffix: {
        value: builderCodeSuffix,
        optional: true
      }
    }
  }]
});

Best Practices

Use with Builder Codes: Register on base.dev to get your Builder Code for proper attribution
Set optional appropriately: Use optional: true if your app can function without attribution tracking
Keep suffixes small: Larger suffixes increase gas costs

For wallet developers implementing dataSuffix support, see the For Wallet Developers section in the Builder Codes guide.

paymasterService - Combine with sponsored transactions
atomic - Use with atomic batch transactions

​Parameters

​Returns

​Example Usage

​Error Handling

​How It Works

​Use Cases

​Builder Codes Attribution

​Best Practices

​Related Capabilities

Parameters

Returns

Example Usage

Error Handling

How It Works

Use Cases

Builder Codes Attribution

Best Practices

Related Capabilities