# What all happens when a command is invoked?

When a non-event sourced command is invoked:

1. pre-conditions are validated
2. command code is executed
3. output returned to the caller (for synchronous calls)

When an event sourced command is invoked:

1. pre-conditions are validated
2. command code is executed
3. event(s) raised
   1. i.e. saved in event-stream
   2. event counter is updated
4. write-handler gets executed
5. event gets published onto the event bus
6. event stable number gets updated
7. output returned to the caller (for synchronous calls)

Note: post condition gets executed at the end only in test-cases