Welcome to tutorial no. 21 in Golang tutorial series. In the previous tutorial, we discussed concurrency and how it is different from parallelism. In this tutorial, we will discuss how concurrency is achieved in Go using Goroutines. What are Goroutines? Goroutines are functions or methods that run concurrently with other functions or methods. Goroutines can be thought of as lightweight threads. The cost of creating a Goroutine is tiny when compared to a thread.