Transactions

Comprehensive guide on Transactions on Sei. Learn key concepts, commands, and best practices.

Sei supports EVM transactions, allowing compatibility with Ethereum-based tools and contracts. Transactions are signed messages originating from an externally owned account (EOA) that trigger state changes on the blockchain.

Transaction Lifecycle

Stage	Description
1. Creation	A transaction is created by an EOA, specifying the recipient, value, gas parameters, and other fields.
2. Signing	The transaction is signed with the sender’s private key to create a valid signature.
3. Submission	The signed transaction is submitted to the network through an RPC endpoint.
4. Mempool	The transaction enters the mempool (transaction pool) where it awaits inclusion in a block.
5. Execution	When selected by a validator, the transaction is executed in the EVM, causing state changes.
6. Validation	The transaction and its state changes are validated by the consensus mechanism.
7. Confirmation	Once validated, the transaction is included in a block and confirmed on-chain.
8. Finality	On Sei, transactions achieve immediate finality once included in a block.

Unlike other EVM chains where you need to wait for multiple confirmations, Sei’s consensus mechanism provides immediate transaction finality. Once a transaction is included in a block, it cannot be reversed.

Gas Mechanics

Gas is a unit of computational work in the EVM that helps prevent spam and allocate resources efficiently:

Term	Description
Gas Limit	The maximum amount of gas the transaction may consume, set by the sender.
Base Fee	The minimum gas price required to be included in a block. On Sei, the base fee is not burned — all fees go to validators.
Priority Fee	An additional fee (tip) paid to validators for faster inclusion.
Gas Price	In legacy transactions, the price per unit of gas the sender is willing to pay.
Effective Gas Price	The actual price paid per unit of gas (base fee + priority fee in EIP-1559).

Gas Requirements for Common Operations:

• Simple SEI transfer: 21,000 gas
• ERC-20 transfer: ~45,000 gas
• Contract deployment: Varies based on contract size and complexity
• Always estimate gas before sending transactions using eth_estimateGas

Transaction Structure

EVM transactions in Sei follow the Ethereum transaction format with standard properties:

Transaction Properties

Property	Description
from	The address of the sender who will sign the transaction. This must be an externally-owned account (EOA) as contract accounts cannot send transactions.
to	The receiving address. If this is an EOA, the transaction transfers value. If a contract address, the transaction executes the contract code. If empty or null, the transaction creates a new contract.
signature	The cryptographic signature generated when the sender’s private key signs the transaction. This confirms the sender has authorized the transaction and includes the v, r, and s components.
nonce	A sequentially incrementing counter that indicates the transaction number from the account. This prevents replay attacks and ensures transaction ordering.
data	The input data (also called ‘input’ or ‘calldata’) for contract execution. For simple transfers, this is usually empty. For contract interactions, this contains the function selector and encoded arguments.
value	Amount of SEI to transfer from sender to recipient (denominated in WEI, where 1 SEI equals 1e+18 WEI).
gasLimit	The maximum amount of gas units that can be consumed by the transaction. Often referred to simply as ‘gas’ in transaction objects.
maxPriorityFeePerGas	The maximum price of the consumed gas to be included as a tip to the validator (denominated in WEI). Used in EIP-1559 transactions.
maxFeePerGas	The maximum fee per unit of gas willing to be paid for the transaction (inclusive of baseFeePerGas and maxPriorityFeePerGas). Used in EIP-1559 transactions.
gasPrice	The price per unit of gas the sender is willing to pay (denominated in WEI). Used in legacy transactions.
chainId	The chain identifier number. Prevents transaction reuse across different chains.
accessList	A list of addresses and storage keys that the transaction plans to access. Used in EIP-2930 and EIP-1559 transactions to reduce gas costs for accessing specified addresses and storage slots.
type	The transaction type: 0 for legacy (pre-EIP-2718), 1 for EIP-2930 access list transactions, and 2 for EIP-1559 fee market transactions.
hash	The transaction hash, a unique identifier for the transaction generated after signing.

Transaction Types

Legacy Transactions (Type 0)

Pre-EIP-1559 transaction format that specifies a single gasPrice.

{
  "from": "0x1923f626bb8dc025849e00f99c25fe2b2f7fb0db",
  "to": "0x07a565b7ed7d7a678680a4c162885bedbb695fe0",
  "gas": "0x55555",
  "gasPrice": "0x1234",
  "value": "0x1234",
  "data": "0xabcd",
  "nonce": "0x0"
}

Access List Transactions (Type 1, EIP-2930)

Transactions with an optional access list of addresses and storage keys to reduce gas costs.

{
  "type": "0x1",
  "from": "0x1923f626bb8dc025849e00f99c25fe2b2f7fb0db",
  "to": "0x07a565b7ed7d7a678680a4c162885bedbb695fe0",
  "gas": "0x55555",
  "gasPrice": "0x1234",
  "value": "0x1234",
  "data": "0xabcd",
  "nonce": "0x0",
  "accessList": [
    {
      "address": "0x07a565b7ed7d7a678680a4c162885bedbb695fe0",
      "storageKeys": [
        "0x0000000000000000000000000000000000000000000000000000000000000000"
      ]
    }
  ]
}

Fee Market Transactions (Type 2, EIP-1559)

Transaction format that supports dynamic base fees with a priority fee tip to validators.

{
  "type": "0x2",
  "from": "0x1923f626bb8dc025849e00f99c25fe2b2f7fb0db",
  "to": "0x07a565b7ed7d7a678680a4c162885bedbb695fe0",
  "gas": "0x55555",
  "maxFeePerGas": "0x1234",
  "maxPriorityFeePerGas": "0x1234",
  "value": "0x1234",
  "data": "0xabcd",
  "nonce": "0x0",
  "accessList": []
}

Example Request

Example Request: Sending an EIP-1559 Transaction

{
  "jsonrpc": "2.0",
  "method": "eth_sendTransaction",
  "params": [
    {
      "from": "0x1923f626bb8dc025849e00f99c25fe2b2f7fb0db",
      "to": "0x07a565b7ed7d7a678680a4c162885bedbb695fe0",
      "gas": "0x55555",
      "maxFeePerGas": "0x1234",
      "maxPriorityFeePerGas": "0x1234",
      "value": "0x1234",
      "data": "0xabcd",
      "nonce": "0x0"
    }
  ],
  "id": 2
}

JavaScript example with web3.js

// Example using web3.js to send a transaction
const Web3 = require('web3');
const web3 = new Web3('https://evm-rpc.sei-apis.com');

async function sendTransaction() {
  const accounts = await web3.eth.getAccounts();
  const sender = accounts[0];

  // Get the current nonce for the sender
  const nonce = await web3.eth.getTransactionCount(sender);

  // Get the current block to estimate gas fees
  const block = await web3.eth.getBlock('latest');
  const baseFeePerGas = block.baseFeePerGas;

  // Set priority fee (tip)
  const maxPriorityFeePerGas = web3.utils.toWei('1', 'gwei');

  // Calculate max fee per gas
  const maxFeePerGas = web3.utils
    .toBN(baseFeePerGas)
    .add(web3.utils.toBN(maxPriorityFeePerGas));

  const tx = {
    from: sender,
    to: '0x07a565b7ed7d7a678680a4c162885bedbb695fe0',
    value: web3.utils.toWei('0.1', 'ether'),
    gas: 21000, // Gas limit for a simple transfer
    maxFeePerGas: maxFeePerGas.toString(),
    maxPriorityFeePerGas: maxPriorityFeePerGas,
    nonce: nonce,
    data: '0x' // Empty data for a simple transfer
  };

  const receipt = await web3.eth.sendTransaction(tx);
  console.log('Transaction receipt:', receipt);
}

sendTransaction().catch(console.error);

Example Response

eth_sendTransaction

{
  "jsonrpc": "2.0",
  "id": 2,
  "result": "0xeba2df809e7a612a0a0d444ccfa5c839624bdc00dd29e3340d46df3870f8a30e"
}

eth_getTransactionByHash

{
  "jsonrpc": "2.0",
  "id": 3,
  "result": {
    "blockHash": "0x5d15649e25d8e7c60b5a1cb3612b6b45dceaa3c774f438d4d5b4e1e1b2db634a",
    "blockNumber": "0x92a",
    "from": "0x1923f626bb8dc025849e00f99c25fe2b2f7fb0db",
    "gas": "0x55555",
    "gasPrice": "0x1234",
    "hash": "0xeba2df809e7a612a0a0d444ccfa5c839624bdc00dd29e3340d46df3870f8a30e",
    "input": "0xabcd",
    "nonce": "0x0",
    "to": "0x07a565b7ed7d7a678680a4c162885bedbb695fe0",
    "transactionIndex": "0x1",
    "value": "0x1234",
    "type": "0x2",
    "accessList": [],
    "chainId": "0x1",
    "maxFeePerGas": "0x1234",
    "maxPriorityFeePerGas": "0x1234",
    "v": "0x0",
    "r": "0x223a7c9bcf5531c99be5ea7082183816eb20cfe0bbc322e97cc5c7f71ab8b20e",
    "s": "0x2aadee6b34b45bb15bc42d9c09de4a6754e7000908da72d48cc7704971491663"
  }
}

Transaction receipt

{
  "jsonrpc": "2.0",
  "id": 4,
  "result": {
    "transactionHash": "0xeba2df809e7a612a0a0d444ccfa5c839624bdc00dd29e3340d46df3870f8a30e",
    "transactionIndex": "0x1",
    "blockHash": "0x5d15649e25d8e7c60b5a1cb3612b6b45dceaa3c774f438d4d5b4e1e1b2db634a",
    "blockNumber": "0x92a",
    "from": "0x1923f626bb8dc025849e00f99c25fe2b2f7fb0db",
    "to": "0x07a565b7ed7d7a678680a4c162885bedbb695fe0",
    "cumulativeGasUsed": "0xd190",
    "gasUsed": "0x5208",
    "contractAddress": null,
    "logs": [],
    "status": "0x1",
    "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
    "effectiveGasPrice": "0x1234",
    "type": "0x2"
  }
}

Transaction Guidelines

Transaction Best Practices:

• Set appropriate gas parameters: Use network conditions to estimate optimal values for maxFeePerGas and maxPriorityFeePerGas.
• Manage nonces carefully: Track and increment nonces correctly to avoid transaction failures.
• Use typed transactions: Prefer EIP-1559 transactions (type 2) for more predictable fees.
• Implement proper error handling: Account for potential transaction failures and revert reasons.
• Verify recipient addresses: Always double-check destination addresses, as transactions cannot be reversed.

Common Issue	Cause	Solution
Transaction Underpriced	Gas price or priority fee too low	Increase maxFeePerGas and maxPriorityFeePerGas
Nonce Too Low	Using a nonce that’s already been used	Query current nonce with getTransactionCount
Out of Gas	Gas limit too low for the operation	Use eth_estimateGas to set appropriate limit
Contract Execution Failed	Contract function reverted	Test with eth_call before sending transaction

Additional Resources

RPC Reference

Complete documentation of Sei’s EVM RPC endpoints for transaction creation and monitoring

Gas & Fees

Learn more about gas calculation, fee estimation, and cost optimization on Sei

Accounts

Understanding Externally Owned Accounts and Contract Accounts on Sei