Efficient Go: Save Memory with Empty struct{}

Go is known for its simplicity and performance, but there are small idioms that can have a surprisingly big impact — especially when it comes to memory usage. One such idiom is the use of the empty struct, written as struct{}.

In this post, we’ll explore:

• What struct{} is
• Why it takes zero bytes
• Where it can help you save memory
• Practical examples to use it effectively

🤔 What is struct{} in Go?

In Go, struct{} is a struct with no fields. That means it holds no data and requires no storage. It’s the smallest possible data structure in Go.

type Empty struct{}

Under the hood, the Go compiler optimizes this to take up zero bytes of memory.

🧠 Why Does struct{} Use 0 Bytes?

Since struct{} has no fields, Go has no reason to assign it memory. In fact, if a struct has only struct{} fields, the entire struct could still occupy zero bytes, unless alignment or padding is needed.

This is in contrast to other types, even if they contain minimal data:

var b bool         // takes 1 byte
var i int          // takes 4 or 8 bytes…