Is it allowed to send messages to the same channel by multiple goroutines simultaneously?

Yes, in Go it is allowed to send messages to a single channel from multiple goroutines simultaneously. Channels in Go are thread-safe and provide synchronization between goroutines.

However, it is important to remember:

• If multiple goroutines write to a single channel and no one reads from it, this will lead to blocking.
• If the channel is buffered, writes will only block when the buffer is full.
• Proper management of channel closing is crucial — only the sender should close the channel, and only when it is sure that no more data will be sent.

Example:

ch := make(chan int)

// Launching multiple goroutines sending data to the channel
for i := 0; i < 3; i++ {
    go func(id int) {
        ch <- id
    }(i)
}

// Reading from the channel
for i := 0; i < 3; i++ {
    fmt.Println(<-ch)
}

Thus, concurrent sending to a channel from multiple goroutines is standard practice in Go.