---
title: "Comment by Synfinity Dynamics Pvt Ltd on \"How I built and scaled real‑time chat app from 2 to millions of users — without a rewrite?\" | Hashnode"
description: "Excellent breakdown of designing for scale from day one. I especially liked the explanation of the transactional outbox pattern and how it keeps the application"
url: "https://hashnode.com/posts/how-i-built-and-scaled-real-time-chat-app-from-2-to-millions-of-users-without-a-rewrite/6a43c12fa4907beae8c291ed/comment/6a465ed54628e35d87a4aa70"
---

[Discussion](https://hashnode.com/posts/how-i-built-and-scaled-real-time-chat-app-from-2-to-millions-of-users-without-a-rewrite/6a43c12fa4907beae8c291ed)

Comment [How I built and scaled real‑time chat app from 2 to millions of users — without a rewrite?](https://hashnode.com/posts/how-i-built-and-scaled-real-time-chat-app-from-2-to-millions-of-users-without-a-rewrite/6a43c12fa4907beae8c291ed)

[Synfinity Dynamics Pvt Ltd](https://hashnode.com/@synfinity-dynamics)

[Jul 2](https://hashnode.com/posts/how-i-built-and-scaled-real-time-chat-app-from-2-to-millions-of-users-without-a-rewrite/6a43c12fa4907beae8c291ed/comment/6a465ed54628e35d87a4aa70)

Excellent breakdown of designing for scale from day one. I especially liked the explanation of the transactional outbox pattern and how it keeps the application tier stateless. Building for horizontal scalability instead of planning for a future rewrite is a smart engineering mindset.

[Nguyen Engineer](https://hashnode.com/@finnng)

[Jul 6](https://hashnode.com/posts/how-i-built-and-scaled-real-time-chat-app-from-2-to-millions-of-users-without-a-rewrite/6a43c12fa4907beae8c291ed/comment/6a465ed54628e35d87a4aa70#reply-6a4b84f495f7b9f7f5782320)

You are right, building horizontal scalability from day one is the point of the experiment.