testrpc

testrpc is a fast Ethereum RPC client for testing and development

You will notice that testrpchas generated 10 addresses with fake ETH you can use without the need to worry about them. This is how testrpcworks by default, but you can make a custom initialization following the documentation. It’s important to mention that testrpstate is volatile, that is every time you close it, the state of your node and accounts will be cleared.

npm install -g ethereumjs-testrpc

testrpc

http://www.jsonrpc.org/specification