---
title: "#high-scale-systems articles | Hashnode"
description: "Explore 2 articles tagged #high-scale-systems on Hashnode. Tutorials, guides, and how-tos from the community."
url: "https://hashnode.com/tag/high-scale-systems"
---

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# #high-scale-systems

2 posts · 0 followers

[Lakshay Dhoundiyal](https://hashnode.com/@LakshayDhoundiyal) · [Sep 12](https://hashnode.com/posts/youtubes-continue-watching-button/6aa5471c3b396c9a7c4ddbf5)

### [The Hidden Distributed System Behind YouTube’s “Continue Watching” Button 🎬⚙️](https://lakshaydhoundiyal.hashnode.dev/youtubes-continue-watching-button?utm_source=hashnode&utm_medium=feed)

How YouTube saves your playback progress, syncs it across devices, and makes one tiny timestamp feel like magic

10 min read · [lakshaydhoundiyal.hashnode.dev](https://lakshaydhoundiyal.hashnode.dev/youtubes-continue-watching-button?utm_source=hashnode&utm_medium=feed)

[Lakshay Dhoundiyal](https://hashnode.com/@LakshayDhoundiyal) · [Sep 4](https://hashnode.com/posts/how-does-gmail-know-a-username-is-already-taken/6a9a6e26433fabf5fd357eb2)

### [How Does Gmail Know a Username Is Already Taken in Milliseconds?](https://lakshaydhoundiyal.hashnode.dev/how-does-gmail-know-a-username-is-already-taken?utm_source=hashnode&utm_medium=feed)

The system-design concepts behind username availability checks, database indexing, caching, APIs, and low-latency distributed systems

10 min read · [lakshaydhoundiyal.hashnode.dev](https://lakshaydhoundiyal.hashnode.dev/how-does-gmail-know-a-username-is-already-taken?utm_source=hashnode&utm_medium=feed)