evmd

cosmos/evm reference chain

Instance.evmd() boots cosmos/evm's reference chain (./cmd/evmd). Its precompiles sit at their canonical x/vm addresses (bank at 0x…0804, staking at 0x…0800, …), which makes it the most faithful target for testing the standard cosmos-evm precompile ABIs.

cosmos/evm ships no official image, so this instance is container-first on an image starskiff builds and publishes (EVMD_DEFAULT_IMAGE) — see Container Runtime. Nothing to install but Docker.

Usage

import { Instance } from 'starskiff';
 
const instance = Instance.evmd({
  accounts: [{ mnemonic: '...', coins: '1000000000000000000000atest' }],
});
await instance.start(); // pulls + runs ghcr.io/2wheeh/starskiff/evmd
 
// eth_chainId → 262144 (x/vm DefaultEVMChainID)

Runtime

Call	Runtime
`Instance.evmd()`	Container, `EVMD_DEFAULT_IMAGE` (starskiff-published, built from cosmos/evm)
`Instance.evmd({ image: 'my/evmd:tag' })`	Container, your image
`Instance.evmd({ binary: 'evmd' })`	Local binary on `PATH`

Defaults

Parameter	Default
`image`	`EVMD_DEFAULT_IMAGE` (`ghcr.io/2wheeh/starskiff/evmd@sha256:dbe4d2…`, digest-pinned, cosmos/evm v0.7.1)
`binary`	`"evmd"` (in-image executable; also the PATH name when opted in)
`chainId`	`"cosmos_262144-1"`
`denom`	`"atest"`
`prefix`	`"cosmos"`
`validatorBalance`	`1e23`
`validatorStake`	`1e22`
`evmPort`	`8545`

What the instance patches

A plain evmd init produces a genesis denominated entirely in stake, with an empty precompile set and no bank denom metadata. The instance fills those gaps:

Precompiles: enables the full x/vm available set (see below).
Denom metadata: writes an 18-decimal bank metadata entry for the native denom (required by the EVM coin-info initialization).
evm_denom: aligned with the instance denom.
Mempool: sets CometBFT's mempool.type = "app" (evmd uses the app-side EVM mempool).
--chain-id on start: Cosmos SDK ≥ v0.54 validates the baseapp chain id against genesis on InitChain.

Precompiles

EVMD_DEFAULT_PRECOMPILES mirrors x/vm's AvailableStaticPrecompiles and is written to evm.params.active_static_precompiles by default, so the bank, staking, distribution and gov precompiles work out of the box. The activeStaticPrecompiles parameter has three-state semantics:

omitted → the instance's default set
explicit undefined → binary default (genesis untouched — empty for evmd)
[] / [...] → disable all / overwrite

import { Instance, EVMD_DEFAULT_PRECOMPILES } from 'starskiff';
 
const instance = Instance.evmd({
  activeStaticPrecompiles: [...EVMD_DEFAULT_PRECOMPILES],
});

The list is normalized to EIP-55 checksummed addresses and sorted by the stored strings before it's written — cosmos-evm genesis validation requires both the canonical casing and ordering.