Our application has so much going on!!! Complex database queries and pages with a lot of information on them cause everything to slow down. Large reports take so long to load that we are stuck waiting instead of analyzing the data. Our users often change their minds about what they want these reports to look like. In this session, you will learn the basics of what an event sourced application looks like and the rules you should follow. You will learn how events can be added to a legacy application and allow you to optimize problem areas. We will discuss the many advantages and few, but significant, disadvantages of using Event Sourcing. organizer notes: This is based on a presentation I gave at my last work all hands meeting, and I am building the talk for PHP Srbija in May. I'm planning to include a useful strategy I used on a project to add an entirely new codebase inside a legacy codeignitor app. This strategy allowed us to replace our application in pieces. This talk will cover areas that my current team is planning to replace to improve our application's reliability and speed up runtimes. We are creating events in the parts of our application that are doing the most work and the events will make it easier for us to separate our read and write transactions and really optimize our runtime. This presentation will be really useful for large, legacy applications with pain points. I will demonstrate how to add this code into your legacy application and ease the pain bit by bit!