# tx Run a transaction with full transaction context and optional RPC state forking. `tx` is similar to [`run`](https://docs.megaeth.com/mega-evme/commands/run) but operates at the transaction level rather than the bytecode level. It handles sender nonces, transaction receipts, and — most importantly — can fork live chain state from a remote RPC endpoint so you can test against real contracts and real storage. ## Usage ``` mega-evme tx [OPTIONS] [RAW_TX] ``` ## Raw Transaction Input The optional `RAW_TX` positional argument accepts a raw EIP-2718 encoded transaction as a hex string. When you provide it, `mega-evme` decodes the transaction and uses it as the base for execution. Any CLI flags you pass alongside it act as **field overrides** on top of the decoded transaction — so you can replay a signed transaction while changing just the gas limit, input data, or any other field. ```bash # Replay a raw signed transaction as-is mega-evme tx 0x02f8... # Replay the same transaction but override the input data mega-evme tx 0x02f8... --input 0xdeadbeef ``` If `RAW_TX` is omitted, `mega-evme` builds the transaction entirely from CLI flags. The default sender is `0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266` and the default gas limit is `10000000`. > **Note:** If the chain ID embedded in the raw transaction doesn't match `--chain-id`, `mega-evme` logs a warning but still proceeds. ## Fork Mode By default, `tx` runs against local state — either empty or loaded from a `--prestate` file. Fork mode fetches account balances, contract code, and storage slots on demand from a remote RPC node, so you can call real deployed contracts without manually constructing their state. | Flag | Default | Description | | ----------------------- | ----------------------- | ------------------------------------------ | | `--fork` | `false` | Enable state forking from RPC | | `--rpc ` | `http://localhost:8545` | RPC endpoint to fork from (env: `RPC_URL`) | | `--fork.block ` | latest | Pin the fork to a specific block number | When `--fork` is set, `mega-evme` connects to `--rpc` and resolves any state reads that aren't covered by a local `--prestate` file against that node. `--fork.block` pins the fork to a specific block's post-state, which is useful for reproducing historical behavior or writing deterministic tests. Without `--fork.block`, the fork uses the latest block at the time of execution. You can set the RPC URL via the `RPC_URL` environment variable instead of passing `--rpc` every time: ```bash export RPC_URL=https://mainnet.megaeth.com/rpc mega-evme tx --fork --sender.balance 1ether --receiver 0x4200000000000000000000000000000000000006 --input 0x06fdde03 ``` Local `--prestate` overrides take precedence over forked state. This lets you patch specific accounts or storage slots while still pulling everything else from the remote node. ## Options `tx` accepts several shared option groups. Each group has its own reference page with the full flag table. | Group | Description | Reference | | ----------------- | -------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------ | | Transaction | Sender, receiver, value, gas, calldata, nonce, tx type | [Transaction Types](https://docs.megaeth.com/mega-evme/reference/transaction-types) | | State management | Prestate file, sender balance, faucet, storage overrides, state dump | [State Management](https://docs.megaeth.com/mega-evme/configuration/state-management) | | Chain / spec | Spec version, chain ID | [Chain and Spec](https://docs.megaeth.com/mega-evme/configuration/chain-and-spec) | | Block environment | Block number, timestamp, coinbase, basefee, gas limit, prevrandao | [Block Environment](https://docs.megaeth.com/mega-evme/configuration/block-environment) | | SALT buckets | Per-bucket capacity overrides for dynamic gas pricing | [SALT Buckets](https://docs.megaeth.com/mega-evme/configuration/salt-buckets) | | RPC cache / retry | Cache size, cache dir, chain-id override, retry and rate-limit | [RPC Cache and Retry](https://docs.megaeth.com/mega-evme/configuration/state-management#rpc-cache-and-retry) | | Tracing | Opcode, call, and pre-state tracers with output options | [Tracing Overview](https://docs.megaeth.com/mega-evme/tracing/overview) | | Output | JSON output mode | See [JSON output](#json-output) below | ## JSON Output Pass `--json` to emit a single `ExecutionSummary` JSON object to stdout instead of the human-readable banner. No banners or diagnostic text are printed in JSON mode — stdout contains exactly one JSON object. The output includes the same fields as [`run --json`](https://docs.megaeth.com/mega-evme/run#json-output), plus one additional field: | Field | Type | Description | | --------- | ---------------- | --------------------------------------------------------------------------- | | `receipt` | `object \| null` | Full transaction receipt with status, logs, gas usage, and contract address | ```bash mega-evme tx --fork --rpc https://mainnet.megaeth.com/rpc \ --sender.balance 1ether \ --receiver 0x4200000000000000000000000000000000000006 \ --input 0x06fdde03 \ --json ``` ## Examples ### Simple call to a contract ```bash # Check WETH balance of the default sender mega-evme tx \ --receiver 0x4200000000000000000000000000000000000006 \ --input 0x70a08231000000000000000000000000f39fd6e51aad88f6f4ce6ab8827279cfffb92266 ``` ### Fork from a remote RPC ```bash # Call WETH.balanceOf against live mainnet state mega-evme tx \ --fork \ --rpc https://mainnet.megaeth.com/rpc \ --sender.balance 1ether \ --receiver 0x4200000000000000000000000000000000000006 \ --input 0x70a08231000000000000000000000000f39fd6e51aad88f6f4ce6ab8827279cfffb92266 ``` ### Fork from a specific block Pinning to a block number makes the execution fully deterministic regardless of when you run it. ```bash mega-evme tx \ --fork \ --rpc https://mainnet.megaeth.com/rpc \ --fork.block 21000000 \ --sender.balance 1ether \ --receiver 0x4200000000000000000000000000000000000006 \ --input 0x70a08231000000000000000000000000f39fd6e51aad88f6f4ce6ab8827279cfffb92266 ``` ### Replay a raw transaction with an override Decode a signed transaction from the mempool or a block, then re-run it with a different gas limit. ```bash mega-evme tx 0x02f8ac... --gas 500000 ``` ### Fork with a patched storage slot Fork live state but override a specific storage slot before execution — useful for testing access-controlled functions. ```bash # Override WETH slot 0 (total supply) and call totalSupply() to verify mega-evme tx \ --fork \ --rpc https://mainnet.megaeth.com/rpc \ --sender.balance 1ether \ --storage "0x4200000000000000000000000000000000000006:0x0=0x0000000000000000000000000000000000000000000000056bc75e2d63100000" \ --receiver 0x4200000000000000000000000000000000000006 \ --input 0x18160ddd ``` For more complex scenarios — multi-step state transitions, contract deployment followed by interaction, and EIP-7702 delegation flows — see the [Cookbook](https://docs.megaeth.com/mega-evme/cookbook). ## Full Help Output ``` Run arbitrary transaction Usage: mega-evme tx [OPTIONS] [RAW_TX] Arguments: [RAW_TX] Raw EIP-2718 encoded transaction (hex). When provided, used as the base transaction with CLI flags serving as overrides Options: --codefile, -v, --log.file, --log.no-color, -h (Same global options as `run`) Transaction Options: --tx-type Transaction type [default: 0] [aliases: --type, --ty] --gas Gas limit [default: 10000000] [aliases: --gas-limit] --basefee Gas price [default: 0] [aliases: --gas-price, --price, --base-fee] --priority-fee EIP-1559 priority fee [aliases: --priorityfee, --tip] --sender Transaction origin [default: 0xf39F...2266] [aliases: --from] --receiver Transaction receiver [aliases: --to] --nonce Transaction nonce --create Create mode [possible values: true, false] --value Value in wei (supports ether/gwei/wei suffixes) --input Calldata as hex [aliases: --data] --inputfile Calldata from file [aliases: --datafile, --input-file, --data-file] --source-hash Source hash for deposit tx [aliases: --sourcehash] --mint ETH to mint for deposit tx (wei) --auth EIP-7702 auth: AUTHORITY:NONCE->DELEGATION [aliases: --authorization] --access EIP-2930 access list: ADDRESS or ADDRESS:KEY1,KEY2,... [aliases: --accesslist] State Options: --fork Fork state from remote RPC --fork.block Block to fork from (default: latest) --rpc RPC URL [env: RPC_URL=] [default: http://localhost:8545] [aliases: --rpc-url] [compat alias: --fork.rpc] --prestate JSON prestate file [aliases: --pre-state] --block-hash BLOCKHASH overrides (repeatable) [aliases: --blockhash] --sender.balance Sender balance (supports suffixes) [aliases: --from.balance] --faucet Add ether: ADDRESS+=VALUE (repeatable) --balance Set balance: ADDRESS=VALUE (repeatable) --storage Set storage: ADDRESS:SLOT=VALUE (repeatable) Chain Options: --spec Spec [default: Rex4] --chain-id Chain ID [default: 6342] [aliases: --chainid] Block Options: --block.number Block number [default: 1] --block.coinbase Coinbase [default: 0x0...0] [aliases: --block.beneficiary] --block.timestamp Timestamp [default: 1] --block.gaslimit Gas limit [default: 10000000000] --block.basefee Base fee [default: 0] --block.difficulty Difficulty [default: 0] --block.prevrandao Prevrandao [aliases: --block.random] --block.blobexcessgas Blob excess gas [default: 0] External Environment Options: --bucket-capacity Bucket capacity (repeatable) State Dump Options: --dump Dump state after the run --dump.output Output file for state dump Output Options: --json Output results as JSON instead of human-readable text Trace Options: --trace Enable tracing --trace.output Output file for trace data --tracer Tracer: opcode, call, pre-state [default: opcode] --trace.opcode.disable-memory Disable memory capture --trace.opcode.disable-stack Disable stack capture --trace.opcode.disable-storage Disable storage capture --trace.opcode.enable-return-data Enable return data capture --trace.call.only-top-call Only trace top-level call --trace.call.with-log Include logs in call trace --trace.prestate.diff-mode Show state diff --trace.prestate.disable-code Disable code in prestate output --trace.prestate.disable-storage Disable storage in prestate output ``` ## See Also * [Transaction Types](https://docs.megaeth.com/mega-evme/reference/transaction-types) — full flag reference for all transaction types * [State Management](https://docs.megaeth.com/mega-evme/configuration/state-management) — prestate files, balance overrides, state dump * [Chain and Spec](https://docs.megaeth.com/mega-evme/configuration/chain-and-spec) — spec selection and chain ID * [Block Environment](https://docs.megaeth.com/mega-evme/configuration/block-environment) — block number, timestamp, coinbase, and more * [SALT Buckets](https://docs.megaeth.com/mega-evme/configuration/salt-buckets) — dynamic gas pricing configuration * [Tracing Overview](https://docs.megaeth.com/mega-evme/tracing/overview) — opcode, call, and pre-state tracers * [Cookbook](https://docs.megaeth.com/mega-evme/cookbook) — worked examples and real-world recipes * [`run`](https://docs.megaeth.com/mega-evme/commands/run) — execute raw bytecode without a full transaction context * [`replay`](https://docs.megaeth.com/mega-evme/commands/replay) — fetch and re-execute an on-chain transaction by hash