This mini-book provides a brief overview of many concurrency topics in Go. Each topic comes with interactive examples — feel free to experiment with them by changing the code and clicking Run . There's also a PDF version with static examples.

This is a quick refresher on Go concurrency, not a beginner's guide. If you want to learn concurrency from the ground up with practical exercises, check out my other book — Gist of Go: Concurrency .

The book is AI-free.

Goroutines • Channels • Select • Pipelines • Time • Context • Wait groups • Data races • Race conditions • Mutexes • Semaphores • Signaling • Run once • Object pool • Atomics • Testing • Scheduling • Diagnostics • Final thoughts

# Goroutines

The foundation of concurrency in Go is goroutines – functions started with the go keyword:

func main () { var wg sync . WaitGroup wg . Add ( 2 ) go func () { defer wg . Done () fmt . Println ( "worker 1" ) }() go func () { defer wg . Done () fmt . Println ( "worker 2" ) }() wg .…