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System Design

The Point To Point Channel

Exactly one consumer handles each message on the channel.

4 min read · core · beat Gold to climb

What it is

A point to point channel delivers each message to exactly one receiver, even when several receivers listen on the same channel. It contrasts with publish subscribe, where every subscriber gets a copy.

How it works

  • Senders place messages on the channel.
  • One or more receivers compete to read.
  • The channel ensures only one receiver consumes a given message.

Why it matters

  • Guarantees a unit of work is processed once, not duplicated.
  • Lets you scale by adding receivers that share the load on the same channel.
  • Fits command style messaging where a task must run a single time.

A point to point channel is the foundation for competing consumers. If two receivers could both take the same message, a payment or order might be processed twice. The channel removes a message once it is handed to a receiver, so peers see only what remains.

Key idea

A point to point channel ensures each message is consumed by exactly one receiver, even when many receivers compete.

Check yourself

Answer to earn rating on the learn ladder.

1. How many receivers consume a given message on a point to point channel?

2. Why does this matter for an order or payment task?