System Design Interview: Design WhatsApp

[@mcw0805]

I was a bit hesitant to watch a short video, but really, this covers the highlights in simple terms

[@tanayvartak4362]

Great! Your explanation is on point and crystal clear. Thanks!

[@hayk.simonyan]

you're welcome! Glad to hear that 👍

[@yingxie9974]

I think your video is very practical in real interview !

[@Coding101-nb5ej]

wow! You consistently impress me with your content, each video is a goldmine of knowledge. thnx for always delivering valuable lessons 👏

[@hayk.simonyan]

My pleasure, glad to hear it's hitting the mark!

[@pankajupreti8967]

good one

[@fitzgerardmouliom443]

awesome, please what will be the type of conplexity we will get why handling groupe discusion excluding media files sharing

[@hayk.simonyan]

group chats will introduce complexities in message fan-out (delivering one message to many), also to storage and synchronization. These can be addressed with techniques like publish/subscribe messaging and server-side sequencing

[@hayk.simonyan]

the complexity generally increases linearly with the number of messages and group members, but optimizations like caching and sharding can help us to manage the overhead

[@MattDeLuco]

Now how do I turn this 7 minutes into a full 1 hour discussion for my interview? 😉

[@mohamedfaizal4360]

Nandri(Thankyou) from India.

[@hayk.simonyan]

You're welcome!

[@moonlight-kh6uz]

Which graphic / infographic tools did you use?

[@hayk.simonyan]

canva

[@moonlight-kh6uz]

@@hayk.simonyan Thanks. Do you first create YT and then Medium, or vice versa?

[@hayk.simonyan]

@@moonlight-kh6uz I first record and publish it on YT, and then convert the same video into an article on Medium

[@ashokchourasia]

Does WhatsApp store messages in database? As per my understanding it stores only the messages which couldn't get delivered at that moment. That, too, for 30 days. Please correct me if i am wrong.

[@mercynik2019]

Yes you are right if you thinks it as way the app works .... they store the messages in user mobile local storage ... and user also has the option to keep a back up over the google drive but they do store the current messages somewhere because when we use the whats app web they loads all the messages we currently have on our phone .... do they collects those from our phones local storage or they do have a backups ? ... thats i also I want to know ... like how it works ......

[@hayk.simonyan]

You're partially correct! WhatsApp does store messages in a database, but it's not just undelivered messages. It stores all messages temporarily on your device to facilitate features like message syncing across devices (mobile and web)

[@moonlight-kh6uz]

Can this be implemented in "C"? Pros/Cons?

[@hayk.simonyan]

C is a viable option if performance and low-level control are important, but if rapid development and modern language features are more important then higher-level languages will be better

[@yaswanthmitta8983]

Why rest apis why not Web sockets?

[@hayk.simonyan]

This is a sample implementation for system design interviews. Therefore, the API design phase refers to these as API endpoints. However, as I mention around 4:00, for real-time chat functionality, the API servers must maintain a websocket connection with the user's device.

[@tanayvartak4362]

Great! Your explanation is on point and crystal clear. Thanks!