Build a Blockchain and a Cryptocurrency from Scratch (Udemy.com)

Nice explanation of the blockchain and how it works. The course systematically explains the concepts step-by-step employing a hands-on approach by implementing the topics in the form of an easy-to-understand (and implement) project. David teaches in a well-paced manner and speaks with a clear voice. Some areas of improvement: 1. Some students (especially one person named Misha) have pointed out a couple of bugs (edge-cases). Fixing them would be a good step. 2. The current implementation stores the chain in memory, so if the peers are switched off, theentire blockchain history is lost. Not sure ifthe actual bitcoin implementation also works this way, but I think storing the blockchain in a json file locally (by each peer) could be a good idea. I should also mention that David also has a separate full-stack version of this course which also has a backend. So, it is possible that he has already taken care of these suggestions in that newer course. Overall, I am satisfied with the course, as it helped me understand LOT of concepts related to how blockchains work.

I really really love this course, first of all it gives me all the logic concerning blockchain how it work, how proof of work work, the concept of mining and other kind of stuffs. Also this course transform me from the beginner level of awareness of Javascript to intermediate level. I recommend this course to take if you want to know in deep the technology of Blockchain. Thank You

I am baffled how someone could teach me to write a blockchain from scratch. I love Node js and when I saw this existed I was overly excited. Currently working on 2 projects in C++ for cryptos and that is a massive headache, since nodejs is already cross platform, this should be the new standard! Going to try and add staking to this code later too! I decided to add notes to almost every file I wrote from this course, I suggest anyone taking this course to do the same... it saved my butt when trying to debug the misspellings and typos, you will make them. I also had to set the course to 0.75 speed to keep up with the typing... David, you type too fast! I am a quick typist but maybe coding isn't second nature as typical qwerty is. I wish you added the course materials to the last 12 lessons, or maybe example files... but I am not complaining. Finding my errors reinforced my learning so maybe it is for the best.

Not for any beginners. A difficult and thoroughly taxing course. The instructor gets to the point and doesn't stop the full course. It was very stressful and there were certain parts I'd wish I'd given up on, but overall this course will truly drill you on blockchain development. Walking away from this course, with some ES6, Python and Golang courses, I feel ready for a blockchain developer position. This class is the core of all of that.

I think this course is the for understanding and implementing the blockchain. each and every word of the code is explained in this. This is simply the best. This course have been very helpful throughout my thesis work which is based on blockchain. One thing which I would like to say is that this course has one missing end. This course teaches us to build the blockchain for only one application which is cryptocurrency. It should gives some tricks to implement it for other applications as well. I mean some thing generic type of code.

I learned a lot of Javascript :) - package management, writing tests were some of the key takeaways. The course is good for absolute beginners and serves well for a basic understanding of almost all aspects of the blockchain. Would have liked it better if it talked about practical difficulties more, say, (1) when all miners are mining and more than one miner finds a solution to the puzzle at the same time - then what would happen? (2) block size limit (3) how does the peer discovery happen? Thanks for the course!

Outstanding course - I have a fully working and tested blockchain thanks to this course! I love the idea of building one big project that combines multiple technologies (blockchain, cryptocurrencies, JavaScript, Jest unit testing, Express web server, REST end points, cryptographic signing/verification). David was super helpful in the Q & A and did an excellent job of breaking everything down into manageable chunks.

Great Course! David explains everything well and helps you get a full understanding of the big picture on the structure of blockchains and cryptocurrency. After completing this course I feel I have a good understanding for what's "under the hood" in a blockchain/cryptocurrency. David was also very responsive for any questions on the project. As a self-taught developer in progress and crypto investor, this course helped me on my journey towards being a blockchain developer and furthering my interest on the subject. Thanks David!

Good explanation from first principle, but still not sure if I could build my own blockchain, for an ICO for example, and whether you do it like this. But the training so far has enlightened me, and totally helped me understand the blockchain. Question, I ask, if I had to run a team of programmers for an ICO (as I already done 30 years of programming, and now wish to move up a notch, and not program) which Udemy course would you do next? with the idea of getting an ICO up and running with smart contract (maybe on Ethereum or EOS blockchain) as soon as possible?

Thanks a lot and respect to instructor. Highly appreciate his patience at creation the course. The thing I really enjoy is to build a blockchain and its api by yourself without touching ethereum and so on. One of the strongest side of the course is that lesson by lesson you add some new functionality to your project by writing code and cover it with a lot of tests. The course is structured, enjoyable, useful and worth educating. This course is a very first step for whom is about to be involved in to the blockchain engineering industry. THANK YOU! :)