eth_call - Tempo RPC Method

Executes a new message call immediately without creating a transaction on Tempo. Used for reading smart contract state.

Why Tempo? Build on a payments-first EVM chain with deterministic settlement and stablecoin-native fees with no native gas token, fees denominated in supported USD stablecoins, and full EVM RPC compatibility.

When to Use This MethodCopy Anchor Link

The eth_call method serves these key scenarios for payment application developers, wallet teams, stablecoin issuers, and treasury automation builders:

• Read smart contract state - Execute view and pure functions to query token balances, DeFi positions, and protocol data without spending gas
• Simulate transactions - Test contract interactions before submitting them on-chain, avoiding failed transactions and wasted gas costs
• Multi-call aggregator queries - Batch multiple read calls into a single request using multicall contracts, reducing API overhead on Tempo
• MEV and arbitrage analysis - Simulate transaction bundles to evaluate profitable opportunities before execution on merchant settlement, treasury operations, payout automation, and stablecoin-native financial applications

Common Use CasesCopy Anchor Link

1. Read ERC20 Token BalanceCopy Anchor Link

Query an ERC20 token contract to retrieve the balance for a specific wallet address using the balanceOf(address) function selector encoded as calldata. The selector is derived from the first 4 bytes of keccak256("balanceOf(address)"), followed by the 32-byte zero-padded address argument.

import { JsonRpcProvider } from 'ethers';

const provider = new JsonRpcProvider('https://api-tempo-mainnet.n.dwellir.com/YOUR_API_KEY');
const tokenAddress = '0x0bd34b0a5be345c9bf7a147eb698e993511180cb';
const walletAddress = '0x0bd34b0a5be345c9bf7a147eb698e993511180cb';

const balanceSelector = '0x70a08231' + walletAddress.slice(2).padStart(64, '0');

async function getTokenBalance() {
  const result = await provider.call({
    to: tokenAddress,
    data: balanceSelector
  });
  console.log('Balance (raw):', BigInt(result).toString());
  return result;
}

getTokenBalance();

2. Query DeFi Protocol StateCopy Anchor Link

Read protocol reserves, price oracles, or user positions from DeFi contracts on Tempo. Each protocol exposes view functions that let you inspect pool state without modifying it - ideal for building analytics dashboards and trading bots.

import { JsonRpcProvider, Interface } from 'ethers';

const provider = new JsonRpcProvider('https://api-tempo-mainnet.n.dwellir.com/YOUR_API_KEY');

const poolAbi = [
  'function getReserves() view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestamp)'
];
const poolInterface = new Interface(poolAbi);
const poolAddress = '0x0bd34b0a5be345c9bf7a147eb698e993511180cb';

async function getPoolReserves() {
  const data = poolInterface.encodeFunctionData('getReserves');
  const result = await provider.call({ to: poolAddress, data });
  const decoded = poolInterface.decodeFunctionResult('getReserves', result);
  console.log('Reserve 0:', decoded[0].toString());
  console.log('Reserve 1:', decoded[1].toString());
  return decoded;
}

getPoolReserves();

3. Simulate a Swap Before ExecutionCopy Anchor Link

Before committing a token swap, call the router contract's quote function to calculate the expected output. This lets you validate slippage tolerance and compare rates across DEXes without risking gas on a failed trade.

import { JsonRpcProvider, Interface, parseEther } from 'ethers';

const provider = new JsonRpcProvider('https://api-tempo-mainnet.n.dwellir.com/YOUR_API_KEY');
const routerAddress = '0x0bd34b0a5be345c9bf7a147eb698e993511180cb';

const routerAbi = [
  'function getAmountsOut(uint amountIn, address[] calldata path) view returns (uint[] amounts)'
];
const routerInterface = new Interface(routerAbi);

async function simulateSwap(amountIn, tokenIn, tokenOut) {
  const data = routerInterface.encodeFunctionData('getAmountsOut', [
    parseEther(amountIn),
    [tokenIn, tokenOut]
  ]);
  const result = await provider.call({ to: routerAddress, data });
  const decoded = routerInterface.decodeFunctionResult('getAmountsOut', result);
  console.log('Expected output:', decoded[0][1].toString());
  return decoded[0][1];
}

simulateSwap('1.0', '0xTokenA...', '0xTokenB...');

Best PracticesCopy Anchor Link

• Use latest for current-state reads and pending for pre-confirmation simulation on Tempo
• Encode function selectors correctly: take the first 4 bytes of the keccak256 hash of the function signature
• Handle revert errors gracefully by parsing the revert reason from the error response data
• For batch reads, use multicall contracts to combine multiple eth_call requests into a single RPC call
• eth_call does not consume gas, making it ideal for unlimited read queries on Tempo

{
  "jsonrpc": "2.0",
  "method": "eth_call",
  "params": [
    {
      "to": "0x0bd34b0a5be345c9bf7a147eb698e993511180cb",
      "data": "0x70a082310000000000000000000000000bd34b0a5be345c9bf7a147eb698e993511180cb"
    },
    "latest"
  ],
  "id": 1
}

Code ExamplesCopy Anchor Link

Error HandlingCopy Anchor Link

Related MethodsCopy Anchor Link

• eth_estimateGas - Estimate gas for transaction
• eth_sendRawTransaction - Send actual transaction