Julien Klepatch
Mentor
(23 reviews)
US$20.00
For every 15 mins
71
Sessions/Jobs
ABOUT ME
Fullstack & Blockchain Software Engineer - Reactjs, Nodejs, Solidity, Ethereum
Fullstack & Blockchain Software Engineer - Reactjs, Nodejs, Solidity, Ethereum
Hi!
I am a software engineer who got bitten by the Blockchain virus couple of years ago. I haven't recovered yet! But that's ok, because Blockchain is the future of everything, right?
Jokes aside, I am passionate about teaching Ethereum Dapps, smart contracts & Blockchain:
- My Manning course: https://www.manning.com/livevideo/ethereum-dapps-in-motion
- My Youtube channel EatTheBlocks: https://www.youtube.com/c/eattheblocks
- My tutorial website EatTheBlocks: https://eattheblocks.com
- My ebook "Learn Ethereum Dapps": https://eattheblocks.com/learn-to-build-an-ethereum-dapp-step-by-step-ebook-tutorial-for-beginners
- My Github repo: https://github.com/jklepatch
- My stack overflow: https://ethereum.stackexchange.com/
I have built consumer and enterprise web applications for the last 5 years. I currently work at LendingBlock, a crypto lending exchange for institutional investors (hedge funds, other exchanges, etc...). Before that, I consulted for various startups and Blockchain projects for the last 5 years. Among other things, I have setup the technical infrastructure of several ICOs (ERC20 tokens and also forking coins, like Monero).
I feel comfortable both on the frontend and on the backend. I have mostly used Nodejs, Javascript and React, and Solidity. I have also used Python for some projects but my experience here is more limited.
I have used MongoDB, but I dont really like it. I much prefer Mysql and RDBM systems in general.
I have worked both in small and big teams. I am very familiar with the agile methodology. I particularly love to use ZenHub and leverage its integration with Github. It's fantastic to manage developer teams and keep in sync the project management with the Github issues.
I have an intermediate knowledge of AWS, Kubernetes and Helm. I know how to setup a basic infrastructure on AWS, a kubernetes cluster, how to setup continuous integration with AWS CodeBuild and how to protect secrets.
Chinese, French, English
Taipei (+08:00)
Joined November 2018
EXPERTISE
5 years experience | 7 endorsements
Javascript was my first programming language. I started to use it on the frontend, then went on to use it on the backend as well with Nod...
Javascript was my first programming language. I started to use it on the frontend, then went on to use it on the backend as well with Node.js.
I started using Javascript when it still only had ES5 features. Back then, the language has many quirks and limitations (and it still has!). But in the meantime, the ES6 revolution came out, and Javascript received a lot of long-awaited updates, like Promises, async/await, destructuration operators, rest/spread operators, among other things. Even though it's still not as nice as working with nice languages like Python, it's getting better.
Because it's such a barebone language, the value of Javascript developer does not depend so much on the mastery of the language itself, but is more dependent on the knowledge of libraries / frameworks. I have lots of experience in React, Redux, 2 of the most popular frontend frameworks for building moderns web applications in 2019.
And finally, in 2019 the future is called Typescript. I develop all my new frontend Javascript project with Typescript 3.
3 years experience | 3 endorsements
Solidity is the most popular programming language for Ethereum smart contract. It's not the best language in the world, but that's the be...
Solidity is the most popular programming language for Ethereum smart contract. It's not the best language in the world, but that's the best we have for developing smart contract, so we have to deal with it.
When developing Solidity smart contract, there are 2 major considerations:
- cost: storing data / doing computation on the blockchain is expensive
- security: once a smart contract has been deployed, its code cannot be changed
Because of this, developing in Solidity is quite different than developing on other platforms. It's actually quite similar to developing on embedded devices / hardware, in terms of constraints.
3 years experience | 3 endorsements
I have been working with Ethereum since 2016. I have experience in smart contract and Dapp development. I have helped many ICOs, includin...
I have been working with Ethereum since 2016. I have experience in smart contract and Dapp development. I have helped many ICOs, including the ICO of Lendingblock (10M USD).
On my youtube channel EatTheBlocks I teach Ethereum / Solidity / Dapp development to more than 1100 subscribers.
5 years experience | 3 endorsements
When React was first introduced at the JSConf US in May 2013, the world of web development was still dominated by jQuery, and nobody gave...
When React was first introduced at the JSConf US in May 2013, the world of web development was still dominated by jQuery, and nobody gave paid much attention to the announcement of React.
Fast-forward to 2019, jQuery is dead, and React is present everywhere. From small websites (that may not need it..) to large-scale applications, everybody is using React.
I had the chance to start working with React as early as 2014 and saw the evolution of the project. In 2019, the ecosystem of React is vibrant:
- There are tons of frontend libraries primarly developed on top of React (React-table, Draft-js)
- Most other frontend libraries have bindings to React: react-bootstrap, D3, etc...
- Testing is top notch with libraries like Jest and Enzyme. You can unit test individual components or do integration testing with full tree rendering, and integrate this in continuous integration pipelines, like you would do for the backend.
I have worked professionally on more than 10 different projects with React for the last 5 years, going from startup prototypes to large-scale enterprise projects. My last project is the frontend trading interface of Lendingblock (200k loc).
5 years experience | 1 endorsement
I have been building application with Node.js since the early days of Node.js.
At the beginning I was building mostly server-rendered ap...
I have been building application with Node.js since the early days of Node.js.
At the beginning I was building mostly server-rendered applications using templating engines like pug or handlebars. Nowadays, I mostly use Node.js for building Rest APIs that talk to frontend applications built with React.
I like the single-thread async nature of Node.js and how it can efficiently use a server. Thanks to recent improvements of ES6 with promises and more recently with async/await, async code with Node.js doesn't look terrible anymore (callback hell...).
I write all my new Node.js applications in Typescript because the entire ecosystem is moving in this direction, and Typescript offers interesting advantages like better intellisense and less needs for unit tests, thanks to the type system.
3 years experience
I have been building Blockchain for clients for the last 3 years, mainly on Ethereum.
I run a youtube channel for Blockchain developers ...
I have been building Blockchain for clients for the last 3 years, mainly on Ethereum.
I run a youtube channel for Blockchain developers (100k views, 2500 subs)
https://www.youtube.com/c/eattheblocks
REVIEWS FROM CLIENTS
(23 reviews)
Robert S Friedman
August 2019
He has good communication and helps with your focus. Looking forward to our next session!
Preet
August 2019
Julien was great! Very responsive, patient, informative, and knowledgable. Highly recommended.
Toby Straumann
July 2019
Excellent mentor in Solidity as well as React
Jiah Lee
July 2019
He helped me with code testing using react-testing-library. I was stuck to grab input values and do event tests due to material-ui and formik layers. He saved me from a headache.
Toby Straumann
July 2019
Thank you Julien for the smart contract review and trubleshooting
mike Le
July 2019
Very knowledgable, great communication, and quick in debugging and resolving my issue. Gave helpful JS tips and advice. Highly recommended!
William Shu
July 2019
Julien was extremely knowledgeable in helping me implement a much-needed feature in my blockchain project. He was constructive during our live session and patiently worked me through the development of my code. I would recommend him as a mentor and judging by his technical expertise, for freelance work as well.
Sara Adam
April 2019
If you are looking for an expert in Ethereum and Solidity so Julien is the person who your are looking for. Julien is very smart, helpful, and supportive . He finishes' the tasks on time and provides a video chat to explain it to you as well . Well done Julien!!
my.reqres
April 2019
An incredibly brilliant engineer who was capable of solving all my problems with thorough attention to detail and instruction. Absolutely highly recommended!
Lewis Allen
March 2019
Helped with everything I needed.
SOCIAL PRESENCE
eattheblocks
Source code for Eat The Blocks, a screencast for Ethereum Dapp Developers
JavaScript
23
7
awesome-monero
Curated list of links of useful resources for the Monero crypto-currency
14
1
302 Reputation
0
1
5
EMPLOYMENTS
Frontend Software Engineer
LendingBlock
2018-01-01-Present
Lendingblock is a crypto exchange for institutional investors for secured crypto lending. For example, you can lend Bitcoin against an Et...
Lendingblock is a crypto exchange for institutional investors for secured crypto lending. For example, you can lend Bitcoin against an Ethereum collateral. During all the time of the loan, Lendingblock holds the collateral of the loan. If an investor does not return the principal at maturity, the collateral is used as a payment.
I was the first employee and built the early prototype in 3 month. We then raised 10 millions USD and hired a team of 10 developers to build the product. I have been working mainly on the frontend, using the following technologies:
React / Redux / Saga / D3 / Storybooks / Jest / Enzyme
I also worked a lot of the smart contract part:
Ethereum / Solidity / Truffle
I have been helping in other areas when needed:
- backend (Python, Asyncio)
- devops (AWS, Codebuild, docker, Kubernetes)
Together, we launched the alpha and the beta of the product and had our first users on testnet.
Node.js
Docker
Bitcoin
View more
Node.js
Docker
Bitcoin
React
JavaScript
Kubernetes
Redux
Ethereum
Solidity
View more
Founder & Instructor
EatTheBlocks
2017-09-01-Present
EatTheBlocks is a Youtube channel to teach Ethereum Dapp and Solidity smart contract development. It has reached 1100 subscribers and is ...
EatTheBlocks is a Youtube channel to teach Ethereum Dapp and Solidity smart contract development. It has reached 1100 subscribers and is growing fast.
I created the channel and I produce all the content.
I provide extra training to members on EatTheBlocks Pro (pro.eattheblocks.com).
Ethereum
Solidity
Web3
View more
Ethereum
Solidity
Web3
DApps
Drizzle
Truffle suite
View more
Fullstack Software Engineer
Self-employed
2014-01-01-2018-12-01
I consulted for various startups. I built web applications (frontend & backend) for consumer-facing applications, in small teams (1-5 dev...
I consulted for various startups. I built web applications (frontend & backend) for consumer-facing applications, in small teams (1-5 developers)
I also worked on Blockchain projects. Among other things, I have setup the technical infrastructure of several ICOs (ERC20 tokens and also forking coins, like Monero).
HTML/CSS
PHP
Node.js
View more
HTML/CSS
PHP
Node.js
MySQL
MongoDB
Redis
Mongoose
Sequelize
JavaScript
Express.js
View more
PROJECTS
Prototype of Crypto Exchange (Lendingblock)View Project
Lendingblock
2018
I have built the prototype of Lendingblock, a crypto lending exchange for institutional investors.
This project took place in the contex...
I have built the prototype of Lendingblock, a crypto lending exchange for institutional investors.
This project took place in the context of the ICO of Lendingblock in March 2018. I made the prototype in 3 month, an incredibly short time for a project this complex, and with only me working on it. Investors praised the demo and it helped a lot to raise our 10 million funding in March 2018, at a moment where the ICO market was very lukewarm.
The prototype of Lendingblock allows to place borrowing and lending orders for crypto assets. For example, if you want to borrow 1 BTC, you can place a borrowing order and specify whats the desired duration and the interest rate of the loan. The backend will match your order automatically with compatible lending orders. The demo has advanced trading charts like order market depth, and rate curves. I also built a market simulator to create fake orders and feed the frontend vizualizations.
This is a video of the prototype in action:
https://www.youtube.com/watch?v=LT38hTab1w0
It covers 7 different repos, accorss the Frontend and the backend. This is the only public github repo (React frontend):
https://github.com/lendingblock/demo-frontend
Node.js
RabbitMQ
React
View more
Node.js
RabbitMQ
React
JavaScript
Redux
View more