Sergey is experienced backend developer specialized in PHP, NodeJS and blockchain development. He provides organized and well-documented source code. Able to perform relational database optimization such as MySQL and Postgresql. Has experience working with full-text search. Worked also with noSQL databases like MongoDB and Cloud Firestore. As for NodeJS, Sergey worked not only with Express and Mongoose, but also with Koa tiny framework. Sergey has different external API integration experience. Payments, cryptocurrency and many other APIs where successfully integrated into PHP and NodeJS apps. Also, he has proven experience working with blockchain Ehtereum. Worked with Ethereum node using Web3 and Geth for several projects already. Sergey is highly responsible, attentive to details and organized.