Darko is available for hire
Hire DarkoDarko Kolev
Verified Expert in Engineering
Python Developer
Location
Skopje, Macedonia
Toptal Member Since
March 17, 2020
Darko specializes in Python and Node.js back-end systems but has experience with front-end JavaScript technologies as well. He's an engaging and proactive developer that loves to contribute to all parts of a project. He has expertise with payment systems, cryptocurrency, dashboards, and projects requiring precise work with real-time data. He writes quality and performant code and strives to deliver exceptional products.
Portfolio
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Solidity, TypeScript, Node.js, React, Blockchain, Ethereum...
BitcoinAverage
WebSockets, REST APIs, InfluxDB, MongoDB, Linux, Redis, JavaScript, Angular...
Freelancer
PostgreSQL, Linux, Stimulus, JavaScript, Django, Python
Experience
Availability
Part-time
Preferred Environment
Linux, WebStorm, PyCharm
The most amazing...
...project I've built is LifeHQ, a personal productivity app. I was the sole developer who also worked on marketing, sales, and product research.
Work Experience
Full-stack Blockchain Developer
2021 - PRESENT
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- Built end-to-end blockchain features, including smart contract deployment, event detection, and front-end integration using Solidity, TypeScript, and React.
- Deployed smart contract across multiple EVM blockchains.
- Used The Graph for smart contract event detection.
Technologies: Solidity, TypeScript, Node.js, React, Blockchain, Ethereum, Ethereum Smart Contracts, Smart Contracts
Lead Developer
2016 - 2020
BitcoinAverage
- Developed a Cryptocurrency exchange aggregator using Celery that polls data from over 50 exchanges in parallel and calculates average prices for Bitcoin and 300+ other cryptocurrencies.
- Designed and implemented the BitcoinAverage REST API using Python and Tornado which is the main product of the company. Maintained and optimized this API for four years.
- Built micro-service architecture for a scalable WebSocket API using Node.js that provides real-time prices and order-book updates to enterprise clients.
- Initiated four types of payment options: PayPal, Stripe, BitPay, and OpenNode in Python.
- Optimized the APIs to handle more requests with intelligent caching with Redis.
- Delivered improvements on front-end systems built with plain JavaScript, AngularJS and Angular 8.
- Stored time series history data in real time using InfluxDB.
- Designed MongoDB architecture for storage of historical and real-time cryptocurrency data.
Technologies: WebSockets, REST APIs, InfluxDB, MongoDB, Linux, Redis, JavaScript, Angular, Node.js, Python
Full-stack Django Web Developer
2018 - 2019
Freelancer
- Designed the architecture and developed LifeHQ, an all-in-one personal productivity application.
- Performed market research, gathered requirements, talked to clients and implemented the app.
- Built a to-do list module, journaling module, habit tracking module, and note-taking module using front-end JavaScript and StimulusJS.
- Created a back-end system with Django and Python3. Designed the database system with PostgreSQL.
Technologies: PostgreSQL, Linux, Stimulus, JavaScript, Django, Python
Back-end Developer
2018 - 2018
3P Development
- Developed an API with Django and Django Rest Framework for an iOS mobile app in the medical industry for performing patient surveys.
- Built a web-based dashboard for generating reports from collected data using Django and vanilla JavaScript.
- Created the database for storing patient data securely and separate from identifiable information in PostgreSQL.
Technologies: REST APIs, Django, Python
Blockchain Smart Contract Developer
2017 - 2017
Omic MD
- Developed a Smart contract in Solidity on the Ethereum blockchain to be used for storing user credits and request approvals.
- Built an adapter and API to interact with the smart contract from a web app.
- Delivered a demo wallet project that demonstrated all capabilities of the smart contract.
Technologies: Ethereum, Node.js, Solidity, Ethereum Smart Contracts, Smart Contracts
Experience
BitcoinAverage Cryptocurrency API
https://bitcoinaverage.comI was the lead back-end developer on the project. I designed a micro-service architecture, developed the public-facing REST and WebSocket APIs, and implemented four types of payment methods: PayPal, Stripe, BitPay, and OpenNode. I optimized the exchange scraper that pulls data from 50+ exchanges and oversaw and maintained the production release of the app for multiple years.
LifeHQ: All-in-one Personal Productivity App
This is a multi-module web application developed with Django on the back end and StimulusJS on the front end. It consists of a to-do list, journaling, note-taking, Pomodoro timer, and habit tracker modules all combined into a single, all-in-one productivity app. I developed LifeHQ as a personal project, something I would want to use for myself.
I performed market analysis, researched competitors, and gathered requirements. I drafted the design and architecture of the system and implemented the full application, both front end and back end. I also oversaw and maintained the production release of the app for multiple years.
I performed market analysis, researched competitors, and gathered requirements. I drafted the design and architecture of the system and implemented the full application, both front end and back end. I also oversaw and maintained the production release of the app for multiple years.
Focus Hub
Social productivity application built with Node.js, MongoJS, Socket.IO, and StimulusJS. I designed the database, the back end, and front-end systems. I built the REST API in Node.js and developed the front end using StimulusJS and Bulma CSS. I implemented live updates and group chat using Socket.IO
The idea of the application is to have a place where remote workers can work productively using customizable Pomodoro cycles and also share their work.
The idea of the application is to have a place where remote workers can work productively using customizable Pomodoro cycles and also share their work.
Articles on Technology, Business, and Productivity
https://medium.com/bitcoinaverage-blogI have written technology documentation for APIs and software libraries, as well as content for my personal blog and the blog of my employer.
API documentation: https://apiv2.bitcoinaverage.com
Employer blog: https://medium.com/bitcoinaverage-blog
Personal blog: https://focusmind.blog
API documentation: https://apiv2.bitcoinaverage.com
Employer blog: https://medium.com/bitcoinaverage-blog
Personal blog: https://focusmind.blog
Blockchain Development Video Course
I created a course called Blockchain Development for Beginners. It consisted of five video tutorials explaining how to get started with blockchain development using Solidity on the Ethereum blockchain. It was showcased on a popular blog.
Skills
Languages
Python, Solidity, SQL, JavaScript, TypeScript
Frameworks
Django, Stimulus, Angular
Libraries/APIs
REST APIs, Node.js, jQuery, React
Storage
MongoDB, Redis, PostgreSQL, MySQL, InfluxDB
Other
Tornadoweb, Algorithms, WebSockets, Cryptocurrency APIs, Writing & Editing, Ethereum Smart Contracts, Smart Contracts
Platforms
Ethereum, Linux, Blockchain
Tools
PyCharm, WebStorm
Education
2010 - 2014
Bachelor's Degree in Computer Science
Ss. Cyril and Methodius University - Skopje, Macedonia
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