Event Sourcing example

Overview

This project has been created to internal presentation at ZEN company. It shows one of the approaches how to make event sourced aggregates.

What problem it resolves?

It resolves the problem with payments in financial institution. Payment can be:

• created, after creation payment is blocked in internal booking system
• resolved by some AML service with statuses IN (REJECT, ACCEPT)
• booked in PSP
• manually corrected by financial institution employee

How it works

• Events are created inside aggregate root
• They are stored by event store (with MongoDB implementation)
• Current payment state is not stored in event store
• Payments are retrieved only by reading events
• To speed up performance, snapshots are created every one 30 seconds