Twitter system design | twitter Software architecture | twitter interview questions

[@atulyadav21j]

There is lot of homework done in any of your video. You just not come up with a any generic solution which could be applied, but actually the solutions which are currently being used in the company (be it twitter/Netflix). Kudos man, great work! :)

[@TechDummiesNarendraL]

Thanks @Atul :)

[@mooa6554]

@@TechDummiesNarendraL Thanks for your videos. Just wanted to know how can we be sure this is the technical stack used in the companies? Any checks you made with the developers of those company?

[@alexeyovriakh2450]

Your work is brilliant. You always include small details like "What is Fanout? Fanout is moving from a single point to different directions.". That level of detail is amazing because you are not taking things for granted (i.e. that everyone knows what a fanout is; I initially always got confused by the concept of fanout actually) it makes it much easier to grasp the material! Thanks!!!

[@deepakzworld]

It is almost impractical to cover each and every aspect of all components that make up a system in a single video, unless it is several hours long. However, Naren does a great job in putting the most important information across in a way that is simple and easy to understand. He also makes sure he uses the exact keywords and terms that interested users can later research on for a more holistic view into every design. Thanks a ton!!

[@hnasr]

There is a lot of work done! You are amazing sir

[@ramendu2812]

Aaayee captain! Nice to see you here, your content is awesome as well. Fun fact, I listen to your podcast on Spotify daily while evening walks :D

[@renon3359]

Read "Grokking the System Design Interview" could not understand much and then came here, and everything made sense. Thank you Narendra for these great videos.

[@shoilirozario6810]

I have seen more than 5 videos and read many more articles. But yours one is the best and well detailed. Thank You.

[@schenschen-xf2ub]

I am preparing for an interview of Amazon, and your video taught me a lot. Thanks and keep it coming!

[@Rekha-pk1ut]

Shen Chen please help me too.. Am. Also preparing for same

[@adistutorials5399]

Rekha Mor good luck!

[@chhltq]

When I research the design for a particular product, I watched at least 3 - 4 videos that explain it on KZbin. And your is always the most complete and relevant. Great job! I think you can consider write a book about system design focusing on interview purpose.

[@flamesdestroy5935]

the best video on twitter system design I've ever seen before in my life

[@jamessunderland9284]

Small nit pick, you want to reverse the order of your redis keys. +- is less efficient than -, think of redis keys as multi-column indices, if you put the random id in front your you effectively double the binary search time. The way you have it the order of your keys might looks like Current Redis --------------------- 123-user 124-tweet 125-tweet 126-user Should Be ---------------- tweet-124 tweet-125 user-123 user-126 If the ratio of tweets to users is not 1:1 you will increase the user lookup time by a factor of the ratio

[@BikasKatwalK]

In Redis is it hash-based lookup from K-V pair or does it use the binary search to find the cache names?

[@jamessunderland9284]

Bikas Katwal that’s a good point. Redis runs in memory, any kv store that uses disk behind the scenes is usually using b-trees

[@galeop]

Great explanations! The only additional things that I learned from other videos (of lesser pedagogical quality): - Regional distribution of cached data (for Reddis) is done thanks to the Writer API (that writes the tweet in the primary region for Reddis + additional regions). - in order to have quick response times between the client and the Write API, the client actually talks to a queue; and the write API picks up messages from that queue.

[@gsb22]

links to those videos?

[@life-is-cat]

I nailed Amazon system design interview question by watching your videos. Just wanted to say thank you and thank you.

[@balajibala2607]

I think for every video you must have read lot of articles , book and compile all the information and delivered in 40 Mins. Keep up the great Job Naren.

[@kumar16pawan]

Now I understand the importance of reading books. I remember this celebrity example was provided in the book name "Designing Data-Intensive Applications: The Big Ideas Behind Reliable, Scalable, and Maintainable Systems". Great Work. More power to you,

[@terigopula]

I loved the way you keep the videos informative enough for the experienced to stay glued and simple enough for the beginners to understand. Great work Narendrea. Appreciate the way you are converting PAPERS to these great VIDEOS.

[@goodbyetube9545]

He is doing fantastic job. Ton to learn from the videos.

[@leonemax6972]

Just saw the Wpp video from 2 months before this. And the difference is enormous kkkkkk. This video is much better. Good work and thank you for the video

[@RS-vu5um]

I agree with the comment from Atul.K.Yadav. Great Job Narendra. You are exceptional in your explanation.

[@zoasonafan1419]

I will call you SIR. You are an amazing teacher. Best explanation.

[@amith89rm]

I came here after clicking on an KZbin recommendation video. I am so glad I got this channel through the recommended videos. I referred so many videos and your video was the best explanation I came across for System Design interview especially taking Twitter as an example. Thanks so much for your videos. Hats off !!! great job. Such an amazing explanation. I wish I had teacher like you!!! Thanks a lot.

[@jamess5330]

Thank you for putting up this tutorial! Study vidoes like this and then practice at Meetapro with mock interviews will help you land multiple offers.

[@jlecampana]

Outstanding System Design video. I think this Twitter Design is more realistic than what other videos on the same topic show. Great work!

[@prasadpulaguntla9255]

Thank you for explaining the overall system design in a such a clear, very easy to understand manner!!

[@ravhaak]

Miles to go before you sleep. Could you please prepare system design and LLD for the following: 1. Simulation of a cricket match, football match etc. 2. Implementation of Queue like Kafka 3. Ecommerce price drop notification system for 50M products 4. Amazon like website and order management system i.e. everything that happens after clicking checkout 5. Elevator system 6. Scrabble 7. Chess game 8. A library for evaluation of expression 9. Stock Trading System 10. Stock Exchange

[@logicboard7746]

Brilliant. Well done managing the details+clarity in 35 mins!

[@mahesh23343]

Absolutely love your work man. Gives so much more confidence when you mention what these companies are actually using. Highly, highly appreciated, thank you!

[@navpreetkaur4902]

very well explained, I could get every bit of the system and much better than many other videos on youtube.

[@mattleahy3951]

Narendra, I'm a big fan of your work. I want you to know that I really appreciate the time and effort that you've put into this. It has helped me a lot to improve my understanding of system design.

[@avvarisaiabhinav2751]

On going through your lectures able to get horizontal approach on many new concepts . very good work. Thank you

[@philipg.5316]

This is a really detailed walk-through of newsfeed system design. Thanks!

[@aplbep]

This is so thorough and specific yet explained in a great way! Shows true mastery of the topic. Thank you very much for your work, really appreciated :D

[@crankerson]

Bravo. This is one of the better system design videos.

[@clarencegomes6076]

There is lot of preparation that you do to come up with these videos. Excellent work!

[@nirmalgurjar8181]

28:35 Inverted Index search is the reason why twitter limits the length of tweet, as you mentioned earlier that we have enough memory now so limiting length of tweet doesn't make sense. I think computing index is the task which puts limit on tweet length.

[@utkarshtripathi2349]

The best video i have ever watched on twitter system design

[@surendrasharma8238]

Hi Narendra, I have just a small suggestion for these system design vidoes. We should make videos a little more conversational. So rather giving exact solution, videos should enable viewers to think about the solution.

[@sagarjaiswal8131]

Hey man! Great work! Well explained! Love to see more coming from you!

[@chankibiswas532]

Your videos are jammed with so much useful knowledge... It's just wonderful... Big thanks

[@sudharsansathiamoorthy1075]

Redis itself has its own zookeeper called "Redis Sentinel" which monitors the redis nodes and if any node is down it will make the another node master.. the selection of the node is based on the priority of the nodes specified with in the redis.conf..

[@shreejitnair2174]

Told all my friends. You are doing a great job.

[@LevKozlodoev]

Thank you also for mentioning the concepts involved (eventual consistency, gather & scatter, fan out, ifti)

[@sanjaysrivastava1100]

Amazing !! 👍 Simple straight forward explanation, well structured in parts, well connected explained in a very nice clear voice. This is complete and comprehensive. I don't know of any video on these topics which comes anywhere near it. Great job man!! keep going !! You do us proud. 👍👍

[@Shini1984]

How to improve: you could provide a more generic architecture one can use, at least partially, during an interview. Current video is extremely detailed. I'd prefer something more generic with more time dedicated to discussing possible realizations, their pros and cons. This video is great as a studying resource, but not so good if you just want a more generic template you can use to architect a system and use it to discuss possible ways to implement a feature or two.

[@moviesandchill7869]

Thank you for posting design questions in such a fast pace. I really like your videos...Keep it coming :)

[@escherita]

Maybe in the future blockchain could help to make Twitter less centralized and more democratic. Thanks for the helpful video!

[@prashantponnala7570]

I've seen so many system design videos and your's are the best. You know your stuff, you keep it to the point, go deep and overall really helpful. Awesome job and many thanks for all your work. A single video cannot cover everything but I would have liked to see how twitter shards users in this design.

[@TechDummiesNarendraL]

@Prashant thanks, Yes Thats the problem. with my day job I dont have much time to make it a series of videos explaining everything / cover every bits and pieces so i keep it simple and important points only.

[@dharmendrabhojwani]

@@TechDummiesNarendraL Nice videos. Now extend them in details please for each component. Would help a lot to everyone. Again Thanks for everything.

[@raisshaikh2105]

Keep Coming. Really appreciate the efforts you are taking to make such valuable source of Information.

[@KailashSharma-zv6lh]

@Naren L: Simply the best and smart. You have acquired such a great knowledge. Wow !!!

[@vercorrobers2278]

I was truly amazed when i discovered your channel . Keep the good work mate!

[@ketansomvanshi3522]

awesome video man ... ! this is relevant to any social media platform design like FB , Linkedin , Instagram.

[@bhupindermanhas1679]

I am short of words .. Awesome stuff man !!

[@hkshetty]

Thank you very much for the simplified explanation!! It cannot be any simpler than this.

[@babulbhanu8213]

I am gonna wish you teachers day forever . Thanks for awesome tutorial :)

[@SPeri6]

I am still at 7:45 but have to say you are very good technically ! Thanks a ton !

[@ajaycj6449]

Best content so far I have come across in days. Really good!!

[@akshayrana3840]

you are the gem master and your videos are gems

[@MuhammadIrshadAli]

Many thanks for making this video :-) You start from basic and go up to advanced concepts in very a easy to understand manner.

[@ibrahimshaikh3642]

Thank u so much for such a detailed explanation of each important topic

[@ghanshyam014]

Well explained with impressive attitude 😉 We're not curious but more eagerly watching how you are doing and finally you done it..😁 Thanks much bro 👊 for your effort and efficiency....😊 Please make more videos and spread your wisdom.. so early you gonna crossing in millions subscriber..... Congrats in advance 💐

[@navsmail]

very good compilation Naren, really like your videos as they are detailed and good quality :)

[@kumarmayank8832]

Hi Naren.... Nice and really informative videos !!! Would request you to put videos for 1) Travel Sites like makemytrip 2) Stock Exchange sites like : Dowjones , Sharekhan 3) Banking Sites - Barclays,ICICI.

[@ravitiwari2160]

Hey, Thank you so much all your knowledge sharing. I am able to perform very nice in all my interviews. Keep up the good work. More power to you. Keep rocking!!!

[@kumarmanish9046]

Good video, most comprehensive. Kindly add subsection/bookmarks.

[@pavant4097]

I haven't subscribed to your channel to get ur latest updates. I have seen ur request to subscribe to your channel at the end of your video. After watching your video, i felt to fulfill your request. This series should be a paid series :). Lot of information you are sharing and i can see that you did lot of homework for each and every video.

[@TechDummiesNarendraL]

Thanks for the kind words :)

[@ankurkesar]

fantastic work bro. You have scaled to a new level :)

[@rockdrigomartineza]

Amazing videos! Congrats! One suggestion could be to use a different microphone to reduce echo and noise and make your voice more clear since for me it seems that every word you say is important! Keep the good work!

[@pallavisingh1673]

Best Twitter system design video I've seen so far.

[@Rupesh209]

Crystal clear system design. Thanks for your time and effort 👍

[@hemantyadav5034]

Thanks Narendra....your videos are really useful. It is very difficult to get such system design explanation with so much details.

[@rkd9915]

Good job Naren. This design video is very well done

[@nehamahajan181]

Really like all of your videos. Thank you for doing the hard work and sharing your knowledge with the community.

[@tarunstv796]

What's the exact use-case for WebSocket here? Is it for - 1. Send a response to the query for search timeline results? 2. Send notifications for new tweets? to my understanding, requests are just sent and then all responses are sent using a WebSocket connection

[@erikadsouza5207]

Thanks Narendra! All your videos are nicely articulated and informative. I am a fan :)

[@jepkofficial]

This video is not bad. Although I would have started and ended with the overall architecture diagram (starting at 30:40) and broken it down over the course of the video. It is also important to note, that this architecture is nothing more than a Writers, Readers, Sockets interface to the underlying backend data stores. Those data stores are each chosen for either their structural properties e.g., fast k/v Redis store for reads ... or for their intermittent processing abilities as found in Kafka Streams for trends data. Nice work.

[@prashantkhisti9617]

Great clarity in the explanation.. demystifies so nicely

[@mayurijain5029]

Fantastic Job Narendra...keep it up...your videos are really very informative and helps to understand core concept of system .Thanks

[@JoeSucksAtGaming]

Thanks for spreading your knowledge man. Greetings from Egypt.

[@sumankumar5126]

One of the best videos of its own kind. Thank you!!

[@VenkeeN17]

Very good explanation. Extremely informative. Thank you :)

[@rajeshk8787]

Thanks for all such wonderful videos Naren. Can you please try to share how online payment systems like Google Pay, Paytm works? Thanks

[@ujagarlamudi]

Amazing work, crystal clear concepts. Thank you!

[@akshaywahi3214]

Awesome one, mate. Wonderful and neat explanation of such a large scale system. Thanks.

[@abhijeetkumar3569]

Hey Narendra, It's really a great explanation and it couldn't be more better. Also this makes perfect sense to me. The problem which I'm facing right now is with microservice architecture. I mean if the same has to be designed in a proper microservice architecture, how we are going to do that? Like in this case the same Redis cluster is shared across different services, which means tight coupling. I would be really thankful if you make a system design video of any system by following microservice architecture. I mean each module will have a context bound and data ownership. And if you already have any video available for the same, please point me to that. Thank you, keep up the great work!

[@tianqizhang1573]

As I know, Redis Cluster does not require Apache ZooKeeper. Redis Cluster has its own built-in mechanisms for node coordination, failure detection, and failover. Please correct me if I am wrong.

[@srinivasanvk57]

very good video. Nicely covered all the topics. Thanks

[@vatsalagrawal4102]

Very happy to see you pasted design diagram image too.. (y)

[@ss53210]

This was very clear and simple to understand. Thank you so much!

[@sandipkumar7251]

One more thing you can cover is, how are adds going to handle by twitter. Because I think this comes as a major feature of Twitter. Thanks for the video :)

[@TechDummiesNarendraL]

@Sandip Sure

[@nandhakumarkr3147]

Thank you Narendra, your videos really helpful

[@user-oy4kf5wr8l]

This system design is really awesome.... i super like it :D it gives me a lot inspiration of designing app like instagram :D thank you!

[@TheDwaipayand]

One question- if someone follows hundred celebrities , then to build home timeline for that person, hundred different queries are required to fetch all tweets as per your design. This does not look scalable design. Am I missing something?

[@yuganderkrishansingh3733]

As mentioned in the video there is a separate list of celebrities maintained that each user is following and while doing the processing for User Timeline that celebrities redis list is checked for new tweets. It might seem like lot of querying but I think this is happening in-memory so it is faster. Also with respect to scalability of this design I would say that the redis cluster that Twitter uses has many nodes so it is not that only one node is doing all the preprocessing for a user timeline.Pls let me know your thoughts.

[@hiteshbitscs]

The great information on twitter architecture....Keep up the good work.

[@samirav608]

Great video, thanks for the simple and clear explanation of concepts

[@pleaseexplain4396]

One quick way I can think of fetching all Tweet related data for the users to display on the user timeline is to shard the user and tweet databases based on geo-location and building indexes on those shards to fetch the user data and tweet data associated with the user to display on the user timeline. Only when we have this I can guess then it makes sense to put this data into a Redis cache, otherwise for the Redis cache to hold this data you would first need to execute a huge Select query on top of the database. Please correct me if I am wrong in my thinking.

[@rewapatilokendra6291]

Thank you for your help, your videos are really very helpful in understanding the real life design system. Thanks much :)

[@dankokozar]

You're a great tutor. Keep up a good work!

[@nishakaramchandani8476]

Great Video. The only part missing is storage estimation, at least for cache..since we are using it extensively in this design. Can you provide some data on storage please?

[@hanibarodaily]

learned a ton❤️ and btw your blue bird drawing is the best lol

[@danisjustcool]

nice work! A very similar solution to yours can be done using Reliable Actors on Service Fabric.

[@ritwikachakroborty6973]

Very useful video..Can you please upload system design videos on parking lot and elevator design.. That will be very helpful Regards Ritwika