eth_estimateGas

const response = await fetch('https://api.1inch.com/web3/56', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    Authorization: `Bearer ${API_KEY}`,
  },
  body: JSON.stringify({
    jsonrpc: '2.0',
    method: 'eth_estimateGas',
    params: [
      {
        type: 'string',
        nonce: 'string',
        to: null,
        from: 'string',
        gas: 'string',
        value: 'string',
        input: 'string',
        gasPrice: 'string',
        maxPriorityFeePerGas: 'string',
        maxFeePerGas: 'string',
        maxFeePerBlobGas: 'string',
        accessList: [
          {
            address: 'string',
            storageKeys: ['string'],
          },
        ],
        blobVersionedHashes: ['string'],
        blobs: ['string'],
        chainId: 'string',
        authorizationList: [
          {
            chainId: 'string',
            nonce: 'string',
            address: 'string',
            yParity: 'string',
            r: 'string',
            s: 'string',
          },
        ],
      },
      'string',
    ],
    id: 1,
  }),
});

const data = await response.json();
console.log(data);