It is so hard to find a decent example of System design interview online. They are mostly for backend not iOS. Thank you for making this video!

Havent seen this kind of clearly explained video...hats off to you..keep it up Andrey !!! 💯

Well done. I'd love to see more of these videos

10:11 this idea is really wise and fresh for me, thank you

Thanks for the video! good luck with your channel!

Great work Andrey.

Excellent video. Thank you.

Thanks for the video! Great explanation

This is one of the bests I have seen till now for System Design for Mobile. The way you explain Andrey is amazing. You clearly explain each bit well enough. I just saw 2 videos only for now but It cleared so many things for me. Thanks for your effort man 👌🩷. Love from India

Very nice video, this was really very clear and concise explanation!

Thanks for the explanation from the interviewer's point of view. Hope it helps you get a job ))

Great & simple explanation. Thanks

Thanks for the explanation. Expecting Many more

The solution to connect a socket with the App to get status was kind of new for me, I will dive in that concept to learn how to implement. thanks for sharing this

Thanks for the video, it was very interesting. Keep posting this kind of content!

cool video, can you tell a little more about api requests and how the synchronization of large databases between the client and the server works?

Thank you so much !!!!!

Hey Andrey. Useful info. Much appreciated. What UI architecture(s) you use at the company you work at?

Andrey, superb demonstration. I'll be sure to rewatch this everytime I am interviewing. Is there any reason you didn't list or opt for SSE (server side events) to receive the status info?

Very good system design I appreciate this.

Real gem.

Great video! But what if we do not make requests with checking the status of a friend every 5 seconds, spending server and device resources on this? After all, information about the statuses of all users is stored in a database on the server, therefore information about status changes is automatically sent to it. If the server has data about all the user's friends, it will be able to send an API request to the application to change the state. After, the application will count the time since the last login offline.

Nice video! Thank you! Friend service represent "Repository", am I right? I still not truly understand NS User Default Module what is that? Is it previous pagination timestamp recorder? Please give more explain. Tks!

Would someone still use bare-bones sockets at this point? With web sockets built into URLSession these days that seems like a better choice almost always?

Also the part when you send GET request with timestap to get only updated list is interesting to me, do you get only like list of people that have updated data(avatar and name) and also if friend is getting deleted from your friend list how do you get that update ?

Андрей, спасибо, очень полезный контент! Молодец! Конструктивный фидбэк: плиз донт хёрт аур иарз виз «аймадж» и «бинд» - «имидж» и «байнд» 😂 Ну а если по делу, интересно, знаком ли ты с материалом канала essential developer? Было бы интересно от тебя услышать что-нибудь в этом роде подробнее об iOS архитектуре.

At what level would this be a question for? Jr, Mid, Senior?

so why we cache it in both disk and memory?

Never heard anyone pronounce 'image' that way 😊

Swinject. You have this mistake in several videos. Also, I'm wondering why SSE is omitted as update mechanism

what if the friends list is long like 1000 or 2000? how should we integrate pagination to it? probaly add 1 more api with pagination along the getFriendList(timeStamp) you were talking about?

ex-colleague here. Really good stuff! Keep it going bro!