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Ganache Core

This is the core code that powers the Ganache application and the Ganache command line tool.

Usage | Options | Implemented Methods | Custom Methods | Unsupported Methods | Testing


ganache-core is written in JavaScript and distributed as a Node.js package via npm. Make sure you have Node.js (>= v8.9.0) installed, and your environment is capable of installing and compiling npm modules.

macOS Make sure you have the XCode Command Line Tools installed. These are needed in general to be able to compile most C based languages on your machine, as well as many npm modules.

Windows See our Windows install instructions.

Ubuntu/Linux Follow the basic instructions for installing Node.js and make sure that you have npm installed, as well as the build-essential apt package (it supplies make which you will need to compile most things). Use the official Node.js packages, do not use the package supplied by your distribution.

Using npm:

npm install ganache-core

or, if you are using Yarn:

yarn add ganache-core


As a Web3 provider:

const ganache = require("ganache-core");

As an ethers.js provider:

const ganache = require("ganache-core");
const provider = new ethers.providers.Web3Provider(ganache.provider());

As a general HTTP and WebSocket server:

const ganache = require("ganache-core");
const server = ganache.server();
server.listen(port, function(err, blockchain) {...});


Both .provider() and .server() take a single object which allows you to specify behavior of the Ganache instance. This parameter is optional. Available options are:

  • "accounts": Array of Object's. Each object should have a balance key with a hexadecimal value. The key secretKey can also be specified, which represents the account's private key. If no secretKey, the address is auto-generated with the given balance. If specified, the key is used to determine the account's address.
  • "debug": boolean - Output VM opcodes for debugging
  • "blockTime": number - Specify blockTime in seconds for automatic mining. If you don't specify this flag, ganache will instantly mine a new block for every transaction. Using the blockTime option is discouraged unless you have tests which require a specific mining interval.
  • "logger": Object - Object, like console, that implements a log() function.
  • "mnemonic": Use a specific HD wallet mnemonic to generate initial addresses.
  • "port": number Port number to listen on when running as a server.
  • "seed": Use arbitrary data to generate the HD wallet mnemonic to be used.
  • "default_balance_ether": number - The default account balance, specified in ether.
  • "total_accounts": number - Number of accounts to generate at startup.
  • "fork": string or object - Fork from another currently running Ethereum client at a given block. When a string, input should be the HTTP location and port of the other client, e.g. http://localhost:8545. You can optionally specify the block to fork from using an @ sign: http://localhost:8545@1599200. Can also be a Web3 Provider object, optionally used in conjunction with the fork_block_number option below.
  • "fork_block_number": string or number - Block number the provider should fork from, when the fork option is specified. If the fork option is specified as a string including the @ sign and a block number, the block number in the fork parameter takes precedence.
  • "network_id": Specify the network id ganache-core will use to identify itself (defaults to the current time or the network id of the forked blockchain if configured)
  • "time": Date - Date that the first block should start. Use this feature, along with the evm_increaseTime method to test time-dependent code.
  • "locked": boolean - whether or not accounts are locked by default.
  • "unlocked_accounts": Array - array of addresses or address indexes specifying which accounts should be unlocked.
  • "db_path": String - Specify a path to a directory to save the chain database. If a database already exists, ganache-core will initialize that chain instead of creating a new one.
  • "db": Object - Specify an alternative database instance, for instance MemDOWN.
  • "ws": boolean Enable a websocket server. This is true by default.
  • "account_keys_path": String - Specifies a file to save accounts and private keys to, for testing.
  • "vmErrorsOnRPCResponse": boolean - Whether or not to transmit transaction failures as RPC errors. Set to false for error reporting behaviour which is compatible with other clients such as geth and Parity. This is true by default to replicate the error reporting behavior of previous versions of ganache.
  • "hdPath": The hierarchical deterministic path to use when generating accounts. Default: "m/44'/60'/0'/0/"
  • "hardfork": String Allows to specify which hardfork should be used. Supported hardforks are byzantium, constantinople, and petersburg (default).
  • "allowUnlimitedContractSize": boolean - Allows unlimited contract sizes while debugging (NOTE: this setting is often used in conjuction with an increased gasLimit). By setting this to true, the check within the EVM for contract size limit of 24KB (see EIP-170) is bypassed. Setting this to true will cause ganache-core to behave differently than production environments. (default: false; ONLY set to true during debugging).
  • "gasPrice": String::hex Sets the default gas price for transactions if not otherwise specified. Must be specified as a hex encoded string in wei. Defaults to "0x77359400" (2 gwei).
  • "gasLimit": String::hex Sets the block gas limit. Must be specified as a hex string. Defaults to "0x6691b7".
  • "keepAliveTimeout": number If using .server() - Sets the HTTP server's keepAliveTimeout in milliseconds. See the NodeJS HTTP docs for details. 5000 by default.

Implemented Methods

The RPC methods currently implemented are:

Management API Methods

Custom Methods

Special non-standard methods that aren’t included within the original RPC specification:

  • evm_snapshot : Snapshot the state of the blockchain at the current block. Takes no parameters. Returns the integer id of the snapshot created. A snapshot can only be used once. After a successful evm_revert, the same snapshot id cannot be used again. Consider creating a new snapshot after each evm_revert if you need to revert to the same point multiple times.

    curl -H "Content-Type: application/json" -X POST --data \
            '{"id":1337,"jsonrpc":"2.0","method":"evm_snapshot","params":[]}' \
    { "id": 1337, "jsonrpc": "2.0", "result": "0x1" }
  • evm_revert : Revert the state of the blockchain to a previous snapshot. Takes a single parameter, which is the snapshot id to revert to. This deletes the given snapshot, as well as any snapshots taken after (Ex: reverting to id 0x1 will delete snapshots with ids 0x1, 0x2, etc... If no snapshot id is passed it will revert to the latest snapshot. Returns true.

    # Ex: ID "1" (hex encoded string)
    curl -H "Content-Type: application/json" -X POST --data \
            '{"id":1337,"jsonrpc":"2.0","method":"evm_revert","params":["0x1"]}' \
    { "id": 1337, "jsonrpc": "2.0", "result": true }
  • evm_increaseTime : Jump forward in time. Takes one parameter, which is the amount of time to increase in seconds. Returns the total time adjustment, in seconds.

    # Ex: 1 minute (number)
    curl -H "Content-Type: application/json" -X POST --data \
            '{"id":1337,"jsonrpc":"2.0","method":"evm_increaseTime","params":[60]}' \
    { "id": 1337, "jsonrpc": "2.0", "result": "060" }
  • evm_mine : Force a block to be mined. Takes one optional parameter, which is the timestamp a block should setup as the mining time. Mines a block independent of whether or not mining is started or stopped.

    # Ex: new Date("2009-01-03T18:15:05+00:00").getTime()
    curl -H "Content-Type: application/json" -X POST --data \
            '{"id":1337,"jsonrpc":"2.0","method":"evm_mine","params":[1231006505000]}' \
    { "id": 1337, "jsonrpc": "2.0", "result": "0x0" }

Unsupported Methods

  • eth_compileSolidity: If you'd like Solidity compilation in Javascript, please see the solc-js project.


Run tests via:

$ npm test