Exactly-once in a microservice environment

If you develop a monolithic app with one database and you do not have external service calls regarding your system, you will probably never face the problems discussed during this talk.

But in the system of several services and with a highload, it's hard to:

• make logical and business transactions perform once;
• send one and only notification to the clients or to give one and only promocode.

The problem is solved by designing idempotent service. In the talk you will learn how it was done and how Kafka and Redis were used to make it possible.