Create an account with a simple operation 'deposit' without event

Transform this operation deposit to an event Note : an event describe a fact that already happened !

Persist account

Reload the state of an account

Create another operation like 'withdraw'

Make commands as input of your system for 'deposit' and 'withdraw'

Dispatch events synchronously, which are listened by a a reader

Make a projection of an account

how to solve concurrency ?

• How to deal with a slow state rebuild ?
• How to deal with two commands fired on a same account ?
• How to deal with the reading order when two events come to the same account ?

Scalability : split them all !