What is the difference between the names of structures starting with a lowercase letter and those starting with an uppercase letter?

In Go (Golang), struct names starting with a capital letter are exported from the package and accessible in other packages. Names starting with a lowercase letter are unexported and only visible within the same package.

Example:

package example

type Person struct { // exported struct
    Name string
}

type employee struct { // unexported struct
    id int
}

Thus, if a struct starts with a capital letter, it can be used outside the package, which is important for organizing a public API. If it starts with a lowercase letter, the struct is hidden inside the package.