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description How to submit transactions on MegaETH — deploy contracts, estimate gas, and debug failures.

Send Transaction

MegaETH is fully EVM-compatible. Point your toolchain at a MegaETH RPC endpoint and everything works — Foundry, Hardhat, Remix, ethers.js, viem, web3.py. For network parameters (chain ID, RPC URLs), see Connect to MegaETH. To bridge ETH or tokens from Ethereum, see Bridge.

Estimate gas correctly

MegaETH's dual gas model charges both compute gas and storage gas. Local EVM simulations (Foundry, Hardhat) only know about compute gas and will underestimate — sometimes by a large margin.

A simple ETH transfer costs 21,000 gas on Ethereum but 60,000 gas on MegaETH (21,000 compute + 39,000 storage). A toolchain that estimates 21,000 will produce a transaction that reverts with "intrinsic gas too low."

The fix: always estimate gas against a MegaETH RPC endpoint or use mega-evme tool to simulate, instead of a local standard EVM.

{% tabs %} {% tab title="Foundry" %}

# Estimate with MegaETH RPC (correct)
cast estimate 0xContract 'myFunction(uint256)' 42 \
  --rpc-url https://mainnet.megaeth.com/rpc

{% endtab %} {% tab title="curl" %}

curl -s https://mainnet.megaeth.com/rpc \
  -X POST -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_estimateGas",
    "params": [{"from":"0xYou","to":"0xContract","data":"0xCalldata"}],
    "id": 1
  }'

{% endtab %} {% endtabs %}

{% hint style="warning" %} The public RPC caps eth_estimateGas at 60M compute gas. If your transaction needs more (e.g., deploying a large contract), either set a manual gas limit or use a managed RPC provider with a higher cap. You can determine the exact gas needed by simulating locally with mega-evme. {% endhint %}

For the full list of pitfalls (volatile data caps, resource limits, receipt interpretation), see Gas Estimation.

Submit transaction

{% tabs %} {% tab title="Foundry (forge create)" %}

# forge create calls eth_estimateGas on the RPC — no local simulation
forge create src/MyContract.sol:MyContract \
  --rpc-url https://mainnet.megaeth.com/rpc \
  --private-key $PRIVATE_KEY

{% endtab %} {% tab title="Foundry (forge script)" %}

# forge script runs local EVM simulation by default, which underestimates gas.
# Use --skip-simulation to bypass local estimation and let the RPC handle it.
forge script script/Deploy.s.sol \
  --rpc-url https://mainnet.megaeth.com/rpc \
  --private-key $PRIVATE_KEY \
  --skip-simulation \
  --broadcast

{% endtab %} {% tab title="cast" %}

# Send a simple ETH transfer
cast send 0xRecipient --value 0.1ether \
  --rpc-url https://mainnet.megaeth.com/rpc \
  --private-key $PRIVATE_KEY

{% endtab %} {% tab title="eth_sendRawTransaction" %}

# 1. Sign the transaction offline (e.g., with cast)
SIGNED_TX=$(cast mktx 0xRecipient --value 0.1ether \
  --rpc-url https://mainnet.megaeth.com/rpc \
  --private-key $PRIVATE_KEY)

# 2. Submit via eth_sendRawTransaction
curl -s https://mainnet.megaeth.com/rpc \
  -X POST -H "Content-Type: application/json" \
  -d "{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"eth_sendRawTransaction\",\"params\":[\"$SIGNED_TX\"]}"

{% endtab %} {% tab title="realtime_sendRawTransaction" %}

# Sign the transaction offline
SIGNED_TX=$(cast mktx 0xRecipient --value 0.1ether \
  --rpc-url https://mainnet.megaeth.com/rpc \
  --private-key $PRIVATE_KEY)

# Submit and get the receipt back in one call — no polling needed
curl -s https://mainnet.megaeth.com/rpc \
  -X POST -H "Content-Type: application/json" \
  -d "{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"realtime_sendRawTransaction\",\"params\":[\"$SIGNED_TX\"]}"

Returns the full transaction receipt directly. Times out after 10 seconds if the transaction has not been executed. See realtime_sendRawTransaction for the full reference. {% endtab %} {% endtabs %}

For key contract addresses (bridge, CREATE2 factory), token lists (stablecoins, LSTs, BTC), and how to bridge tokens onto MegaETH, see Contracts & Tokens. To bridge assets from Ethereum, see Bridge.

Debug a failed transaction

When a transaction reverts, MegaETH provides two debugging tools:

  1. debug_traceTransaction — standard Ethereum debug RPC, available through managed providers like Alchemy.
  2. mega-evme — MegaETH's local transaction simulation tool. No RPC provider needed.

{% tabs %} {% tab title="mega-evme (replay)" %}

# Replay a failed transaction with call-level tracing
mega-evme replay 0xYourTxHash \
  --rpc https://mainnet.megaeth.com/rpc \
  --trace --tracer call

{% endtab %} {% tab title="mega-evme (what-if)" %}

# Would the transaction succeed with more gas?
mega-evme replay 0xYourTxHash \
  --rpc https://mainnet.megaeth.com/rpc \
  --override.gas-limit 30000000

{% endtab %} {% tab title="cast (debug RPC)" %}

# Requires a provider that supports debug_traceTransaction
cast rpc debug_traceTransaction 0xYourTxHash \
  --rpc-url https://your-alchemy-endpoint.com

{% endtab %} {% endtabs %}

Common failure causes:

Symptom Likely cause Fix
intrinsic gas too low Gas estimated by local EVM, missing storage gas Estimate against MegaETH RPC
out of gas with low compute usage Storage gas exceeded the limit Increase gas limit or reduce state writes
out of gas after reading block.timestamp Volatile data access caps compute gas to 20M Split work across multiple transactions
resource limit exceeded Hit data size, KV updates, or state growth cap Reduce state operations per transaction

For the full debugging guide, see Debugging Transactions.

Understand execution semantics

MegaETH is EVM-compatible, but the execution model has differences that affect gas costs and transaction behavior. The key concepts:

  • Dual gas model — every transaction pays compute gas + storage gas. See Gas Model.
  • Resource limits — per-transaction caps on data size, KV updates, and state growth beyond gas. See Resource Limits.
  • Volatile data access — reading block.timestamp, block.number, or oracle data caps compute gas to 20M. See Volatile Data Access.
  • System contracts — oracle, high-precision timestamp, and keyless deployment at fixed addresses. See System Contracts.

For the complete list of behavioral differences, see EVM Differences.