Read EVM smart contract state and decode ABI-encoded return values with Zafeguard components.

Read & Decode

Components for reading on-chain state and decoding ABI-encoded data — without sending any transactions.

Public RPC URLs enforce rate limits per IP address and can fail under concurrent load. Use a private endpoint (Alchemy, Infura, QuickNode, or self-hosted). See Connecting to any chain.

READ_EVM_CONTRACT

READ_EVM_CONTRACT Workflow Component

Call a read-only (view / pure) contract function using eth_call. Returns the raw ABI-encoded result — pipe into DECODE_EVM_FUNCTION_RESULT to extract the values.

Config

None.

Inputs

Field	Type	Description
`jsonRpcUrl`	`string`	JSON-RPC endpoint
`contractAddress`	`string`	Target contract address
`calldata`	`string`	ABI-encoded calldata (from `BUILD_EVM_CALLDATA`)

Outputs

Field	Type	Description
`result`	`string`	Raw ABI-encoded return data (hex)

Example: read ERC-20 balance

BUILD_EVM_CALLDATA (balanceOf ABI, [holder_address])
        │ calldata
        ▼
READ_EVM_CONTRACT (jsonRpcUrl, token_contract)
        │ result
        ▼
DECODE_EVM_FUNCTION_RESULT (balanceOf ABI, result)
        │
        ▼ balance (uint256 as string)

DECODE_EVM_FUNCTION_RESULT

DECODE_EVM_FUNCTION_RESULT Workflow Component

ABI-decode the raw bytes returned from a contract call into typed values.

Config

Field	Type	Required	Description
`functionName`	`string`	Yes	Name of the function whose return type should be used for decoding (e.g. `"balanceOf"`)

Inputs

Field	Type	Description
`abi`	`AbiItem[]`	ABI containing the function definition
`encodedResult`	`string`	Raw hex-encoded return data (output of `READ_EVM_CONTRACT`)

Outputs

Outputs are dynamic — one output per return value in the function's ABI definition. They are indexed as 0, 1, 2, etc. (matching the order of outputs in the ABI).

Field	Type	Description
`0`	depends on ABI	First decoded return value
`1`	depends on ABI	Second decoded return value (if any)
`...`	depends on ABI	Additional return values

SDK example

import { WorkspaceClient, ComponentModule } from '@zafeguard/caller-sdk';
const workspace = new WorkspaceClient({ apiKey: process.env.ZAFEGUARD_API_KEY! });

// 1. Encode balanceOf(address) call
const calldata = await workspace.call(ComponentModule.BUILD_EVM_CALLDATA, {
  abi: [{
    type: 'function',
    name: 'balanceOf',
    inputs: [{ name: 'account', type: 'address' }],
    outputs: [{ name: '', type: 'uint256' }],
    stateMutability: 'view',
  }],
  args: ['0xHolderAddress'],
}).promise();

// 2. Read contract
const raw = await workspace.call(ComponentModule.READ_EVM_CONTRACT, {
  jsonRpcUrl: 'https://eth-mainnet.g.alchemy.com/v2/KEY',
  contractAddress: '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48', // USDC
  calldata: calldata.calldata,
}).promise();

// 3. Decode
const decoded = await workspace.call(ComponentModule.DECODE_EVM_FUNCTION_RESULT, {
  abi: [/* same ABI */],
  encodedResult: raw.result,
}).promise();

console.log(decoded.decoded[0]); // "1000000" (1 USDC)

Field	Type	Description
`data`	`string`	Hex-encoded data to hash (`0x...` or without prefix)

Outputs

Field	Type	Description
`hash`	`string`	keccak256 hash (`0x...`, 32 bytes)

SDK example

import { WorkspaceClient, ComponentModule } from '@zafeguard/caller-sdk';
const workspace = new WorkspaceClient({ apiKey: process.env.ZAFEGUARD_API_KEY! });

const hash = await workspace.call(ComponentModule.EVM_KECCAK256, {
  data: '0x095ea7b3', // approve(address,uint256) selector input
}).promise();
console.log(hash.hash); // "0x..."

Read & Decode

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