Roman Butusov

Using Golang, designed, developed, ran and administered a custom email system for a client that receives 100,000 emails daily. Developed a Client-Server solution for extending Xojo applications as required by a client, by utilizing LLVM bitcode, on-demand remote compilation and linking cross-platform projects. Technologies and frameworks used: Golang, LLVM, Iris, Gorm and more.

Worked on Polygon/Hermez ZK-Rollup open source project.

Designing, planning and writing smart contracts for the main Ethereum network and sidechains. Experienced with many modern Ethereum token standards. Extended some of those, e.g. implemented gasless token transactions for an Ethereum sidechain. I've been creating backend services that interact with various blockchains to facilitate the blockchain integration into the current project. Worked with many blockchain/sidechain service providers, to name a few: Polygon/Matic, Biconomy, Fortmatic, The Graph.

Worked on several blockchain related projects for different clients. Designed and implemented an ERC20 coin block explorer for the Ethereum blockchain. Designed the architecture, the data model and coded the backend API. Technologies used: parity, mongodb, several daemons processing the data coded in Golang. Implemented a private ERC20 coin based on Ethereum's Proof of Authority consensus. The client would control the coin emission and distribution in a secure, permissioned blockchain.

Designing and integrating (from scratch) the infrastructure foundation. Using exclusively the Docker paradigm in design, developing and ops. Using Rancher as the orchestration suite, an early Rancher user in production since version 1.0.Experienced in flexible service scaling and balancing practices. Solving the common problem of the centralized data storage for Docker. Providing zero-downtime service upgrades and releases. Designing and developing of a custom cryptocurrency based on the Quorum blockchain.

System administation and technical support for a web hosting company with more than 1000 clients. Duties include provisioning, copying, deploying, migrating customer web sites. Finding bottlenecks in web sites performance and fixing it quickly. Solving web site and database performance issues. Operating a big server park that contains a lot of managed and unmanaged servers with customer hosted web sites. Deploying load balanced clustered setups for busy websites. Making a good use of nginx, PHP, mysql.

Creating/deploying, migrating (with zero downtime) and configuring web sites. Load optimizations, quick discovering of bottlenecks in performance. Configuring and optimizing nginx, Apache, Mysql. Creating and configuring of test and staging environments for web developers. Hardware and service monitoring using Zabbix. Writing own Zabbix scripts for complex monitoring. Websites load monitoring using pinba with Zabbix integration. Database performance monitoring. Writing scripts for administrative tasks.