Channels are one of the most recognizable features of Go. Beginners often fall in love with them instantly. They look clean. They look safe. They feel like a built-in solution to concurrency. And then, slowly, problems appear. Deadlocks. Goroutines that never exit. Pipelines that stall under load. Systems that work perfectly in tests and fail in production.
Almost always, the root cause is the same misunderstanding: channels are treated like queues.
They are not.
A channel is not a data structure. It is a synchronization mechanism that happens to move values. If you treat it like a queue, you will eventually design yourself into a corner. If you treat it like a coordination tool, your concurrent code becomes simpler, safer, and easier to reason about.
Let’s rebuild the mental model from scratch.
When you write this:
ch := make(chan int)
go func() {
ch <- 42
}()
v := <-ch
fmt.Println(v)
Two things happen, not one.
A value moves from sender to receiver.
Execution is synchronized.
The send cannot complete until the receive is ready. The receive cannot complete until the send happens. This handshake is the essence of an unbuffered channel. The value transfer is almost secondary.
This is why unbuffered channels are sometimes called rendezvous points. They force goroutines to meet.
Now let’s add a buffer:
ch := make(chan int, 2)
ch <- 1
ch <- 2
At first glance, this looks like a queue. You put things in, you take things out. But the semantics are already different. The buffer only delays synchronization; it does not remove it. The third send will still block. The receive will still establish ordering. The channel is still about coordination, just with more slack.
This distinction matters more than it seems.
Beginners often write code like this:
tasks := make(chan Task)
go producer(tasks)
go consumer(tasks)
And then wonder: who closes the channel? What happens if the producer exits early? What happens if the consumer is slower? What happens if there are multiple consumers?
These questions feel annoying at first. But they are not implementation details. They are design questions. Channels force you to answer them because channels encode ownership.
Only the sender should close a channel.
Closing a channel signals “no more values will ever arrive.”
Closing is not cleanup. It is a broadcast event.
This is why closing a channel from the receiver side is almost always a bug.
Consider this pattern:
go func() {
for v := range ch {
process(v)
}
}()
This loop only exits when the channel is closed. That means the sender controls the lifetime of the receiver. This is not accidental. It is the channel expressing a protocol.
Problems begin when channels are used without a protocol.
ch := make(chan int)
go func() {
ch <- 1
}()
// Who closes ch?
This channel has no clear owner. No termination signal. No lifetime rule. It works for now — until it doesn’t.
Now let’s talk about buffering mistakes.
Beginners often add a buffer to “fix” a deadlock.
ch := make(chan int, 100)
The deadlock disappears. The program runs. Everyone is happy. Until memory grows. Or latency spikes. Or goroutines pile up. Buffers do not fix coordination problems. They hide them.
A buffer should exist because it models reality, not because it makes the program stop blocking.
For example, a worker pool:
jobs := make(chan Job, 10)
for i := 0; i < 5; i++ {
go worker(jobs)
}
Here the buffer represents a queue of pending work. That is a valid use. But even here, the channel is still enforcing coordination. If producers outrun consumers, the buffer fills and applies backpressure. This is not an accident — it’s a feature.
Another common beginner mistake is assuming channels imply fairness.
ch := make(chan int)
go func() { ch <- 1 }()
go func() { ch <- 2 }()
fmt.Println(<-ch)
fmt.Println(<-ch)
There is no guarantee which value arrives first. Channels do not schedule goroutines. The scheduler does. Channels only synchronize when communication happens, not who gets to communicate first.
This is why channels should not be used to encode priority or ordering unless you explicitly design for it.
One of the most powerful realizations is this: channels are best used at the boundaries of ownership.
Inside a goroutine, use normal variables.
Between goroutines, use channels to hand off responsibility.
For example:
go func() {
result := compute()
results <- result
}()
The goroutine owns result. The moment it sends it, ownership transfers. After the send, the goroutine should not touch that value again. This mental rule eliminates an entire class of bugs.
This also explains why sharing pointers through channels is dangerous unless you are careful. The channel does not protect you from shared mutable state. It only synchronizes the moment of transfer.
Channels are not magical. They are explicit. And that explicitness is what makes them powerful.
When beginners struggle with channels, it is usually not because channels are hard. It’s because the design is unclear. Who owns what? Who decides when things stop? What does closing mean? What does blocking mean?
Once you answer those questions, channels stop feeling mysterious.
By now, a pattern should be emerging.
Memory model → lifetimes.
Pointers → ownership.
Goroutines → scheduling.
Channels → coordination.
Everything fits together.
In the next part, we’ll talk about context. Not as a cancellation trick, but as a protocol that ties together lifetimes, goroutines, and ownership across API boundaries. This is where many Go codebases quietly go wrong — and where understanding pays off immediately.
Want to go further?
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