---
title: "Discussion on \"What Is a Message Queue? How Apps Talk Without Waiting for an Answer\" | Hashnode"
description: "Discussion on \"What Is a Message Queue? How Apps Talk Without Waiting for an Answer\". Calling another service directly is like phoning someone and waiting on the line — a queue is like leaving a note on their desk"
url: "https://hashnode.com/posts/what-is-a-message-queue-how-apps-talk-without-waiting-for-an-answer/6af66c8ff3d327dd6219d95e"
---

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# [What Is a Message Queue? How Apps Talk Without Waiting for an Answer](https://itsmeminsithu.hashnode.dev/what-is-a-message-queue-how-apps-talk-without-waiting-for-an-answer?utm_source=hashnode&utm_medium=feed)

Calling another service directly is like phoning someone and waiting on the line — a queue is like leaving a note on their desk

2d ago · 7 min read · itsmeminsithu.hashnode.dev  
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-   [#architecture](https://hashnode.com/tag/architecture)
-   [#backend](https://hashnode.com/tag/backend)
-   [#microservices](https://hashnode.com/tag/microservices)
-   [#software-design](https://hashnode.com/tag/software-design)
-   [#scalability](https://hashnode.com/tag/scalability)

## Written by

[Min SiThu](https://hashnode.com/@itsmeminsithu)

@itsmeminsithu · Singapore

  
[View profile](https://hashnode.com/@itsmeminsithu)

Software Engineer

Nubbad Developer. | Now I accidentally create problems.

## Responses 1

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[OneLifeVibe](https://hashnode.com/@onelifevibe)

[2d ago](https://hashnode.com/posts/what-is-a-message-queue-how-apps-talk-without-waiting-for-an-answer/6af66c8ff3d327dd6219d95e/comment/6af6bb56edfd23c8008d672f)

The phone call versus leaving a note analogy is the clearest way I have seen this explained. The checkout example with order 4821 makes the failure mode concrete, because one slow step should not hold the customer on the line. I also liked the honest trade off in the table, that the sender gives up knowing exactly when the job finishes. Starting with a dead letter tray from day one is practical advice I will remember.