Evgenii Pecherkin, Developer in Montreal, QC, Canada
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Evgenii Pecherkin

Verified Expert  in Engineering

Back-end Developer

Montreal, QC, Canada
Toptal Member Since
September 7, 2022

Evgenii is a hard-working, dedicated team player and an experienced back-end engineer. He has more than 11 years of practical experience, including everything about software development, design, integration, and solving all kinds of issues, as well as creating new systems from scratch and supporting and updating legacy systems. Evgenii provides reliable performance, as well as transparent and effective communication.


Node.js, TypeScript, React, PostgreSQL, Docker, Kubernetes...
Above Lending Inc
Ruby on Rails (RoR), Amazon Web Services (AWS), PostgreSQL, Kubernetes, Docker...
Ruby, Ruby on Rails (RoR), Microservices, PostgreSQL, Jenkins, Agile...




Preferred Environment

Ruby on Rails (RoR), PostgreSQL, Docker, TypeScript, React, GitHub, Jira, Slack, Agile, Python

The most amazing...

...thing I've achieved is a noticeable contribution to the performance and stability of Toptal's platform.

Work Experience

Chief Technology Officer

2021 - PRESENT
  • Researched, compared, and selected tools and technologies for creating the product and designed the system architecture, considering the cost of cloud services, anticipated user growth, and the business's strategic direction.
  • Developed several critical components of the application, including integration with blockchain, content moderation using Telegram, an administration module, and CI/CD pipelines.
  • Led a 4-person engineering team to launch the product into production within four months.
  • Contributed significantly to developing the product vision from a preliminary idea. Proposed numerous ideas and solutions, many of which proved essential for the business and were later patented.
  • Built an in-house hosting solution for the project, consisting of four machines with Kubernetes deployed on them.
Technologies: Node.js, TypeScript, React, PostgreSQL, Docker, Kubernetes, Google Kubernetes Engine (GKE), Google Cloud Platform (GCP), Blockchain, Agile, CI/CD Pipelines, Jira, Slack, GitHub, Blockchain Platforms, Customized Blockchains, Git, Vim Text Editor, Stripe, Stripe API, Stripe Checkout, APIs, GraphQL, Ethers.js, Ethereum, Non-fungible Tokens (NFT), System Design, Scaling, Performance, Debugging, CQRS, OOP Designs, API Architecture, JavaScript, Stripe Connect, Stripe Payments, Stripe Connect API, API Integration, API/Services Architecture, Unix, Optimization, IT Management, Team Leadership, Remote Team Leadership, Analytics, Research, Microservices, Microservices Architecture, CTO, Front-end, Back-end, HTML, CSS, Full-stack, Jest, NestJS, TypeORM, Fintech, Digital Payments, Card Payments, Stripe Subscriptions, Stripe Terminal, Software Architecture, Leadership, Technical Leadership, Social Media Apps, Startups, Architecture

Senior RoR Developer

2022 - 2023
Above Lending Inc
  • Participated in the analysis and redesign of the legacy system, which was written in pure JavaScript. Identified several crucial issues in the new design, proposed alternative solutions, and prepared an implementation plan.
  • Resolved various architectural and performance issues by transitioning responsibilities from the Ruby on Rails service to NGINX.
  • Simplified the domain logic design and enhanced its stability, scalability, and testability through effective application of object-oriented programming principles. Educated other developers in these practices to ensure the project's future success.
  • Improved the efficiency significantly and reduced the resource load of CI/CD processes by optimizing Dockerfiles.
  • Developed an intelligent microservice to maintain data consistency between the legacy and new systems.
  • Enhanced the handling of background asynchronous tasks by decoupling long-running tasks and adopting a publish-subscribe model for third-party integrations.
Technologies: Ruby on Rails (RoR), Amazon Web Services (AWS), PostgreSQL, Kubernetes, Docker, Global Banking, Kibana, Grafana, TypeScript, API Architecture, GraphQL, IT Systems Architecture, Optimization, Full-stack Development, Back-end, Git, CI/CD Pipelines, Third-party APIs, PostgreSQL 10, Jenkins, DevOps, NGINX, Microservices Architecture, Research, Analytics, Data Processing, Fintech, Online Banking, Digital Payments, Enterprise, Software Architecture, Architecture

Core Senior Back-end Developer

2016 - 2021
  • Optimized CI processes, achieving a 30% speed increase and cost reduction, saving thousands of hours and over $10,000 monthly. Developed a tool for parallel execution of RSpec and Cucumber tests via DRb protocol.
  • Enhanced the overall performance of the application by identifying and resolving multiple bottlenecks, utilizing tools such as Grafana, Kibana, and flame graphs.
  • Improved user experience by transitioning a portion of the interface from Ruby on Rails views to React.
  • Reworked legacy Delayed Job jobs to Active Job, refactoring them to align with industry best practices.
  • Simplified job handling in Active Job by introducing an innovative concept of serializers. This concept was later integrated into Active Job itself.
  • Increased the system's consistency and fault tolerance by introducing a new abstraction level to represent business transactions during the execution of business processes. This included managing data with complex dependencies on external systems.
  • Optimized RAM usage of the Cucumber suite through object caching in factories.
  • Developed a regression test selection library for RSpec. It constructs a dependency tree linking test files to source files, which is then utilized to select and execute specific tests based on the changes in source files.
Technologies: Ruby, Ruby on Rails (RoR), Microservices, PostgreSQL, Jenkins, Agile, CI/CD Pipelines, Jira, Sidekiq, Redis, Slack, GitHub, Grafana, Kibana, Git, NGINX, Amazon Web Services (AWS), GitHub API, APIs, GraphQL, REST APIs, CQRS, System Design, OOP Designs, API Integration, Domain-driven Design (DDD), Test-driven Development (TDD), GitFlow, Microservices Architecture, API Architecture, API/Services Architecture, Node.js, Python 3, Django, Vim Text Editor, Linux, Unix, Debugging, Performance, Optimization, Apache Kafka, Front-end, Back-end, HTML, CSS, Enterprise, Architecture

Senior Ruby, Ruby on Rails, and React Developer

2014 - 2016
Online Freelance Agency
  • Upgraded a legacy file management system from Ruby 1.8 to 2.7, aligning it with industry best practices and boosting overall performance by 30% through Active Job, Sidekiq, and concurrent processing.
  • Enhanced a legacy Backbone and jQuery application by migrating it to React, improving performance and reducing complexity.
  • Developed a real-time chat feature for a social network using WebSockets.
  • Created a non-intrusive tracking subsystem by launching a new Ruby microservice and configuring NGINX, ensuring zero interference with the main application.
Technologies: Ruby, Ruby on Rails (RoR), PostgreSQL, MySQL, MongoDB, React, ECMAScript (ES6), ES7, Node.js, Agile, CI/CD Pipelines, GitHub, Slack, Sockets, NGINX, Git, JavaScript, Stripe, Stripe API, Stripe Checkout, APIs, REST APIs, GraphQL, Debugging, Optimization, Performance, API Design, System Design, API/Services Architecture, Linux, Unix, Docker, Stripe Connect, Stripe Marketplace, Stripe Connect API, OOP Designs, Analytics, Research, GitHub API, GitFlow, Vim Text Editor, Microservices, Microservices Architecture, Front-end, Back-end, HTML, CSS, Full-stack, Jest

Ruby on Rails Developer

2013 - 2014
  • Reworked a business task processing subsystem by implementing a custom Delayed Job processor, boosting throughput from 100 to 1,000 tasks per hour.
  • Improved full-text search efficiency in the system, doubling performance through Elasticsearch integration.
  • Mentored junior developers, ensuring their alignment with the main team's quality and performance standards.
  • Developed a microservice-based system for uploading, transforming, storing, and streaming videos, images, and audio, employing diverse technologies.
Technologies: Ruby, Ruby on Rails (RoR), Docker, PostgreSQL, Redis, Sidekiq, Data Processing, CI/CD Pipelines, Agile, Elasticsearch, Streaming, Sockets, NGINX, Git, JavaScript, Stripe, Stripe API, Stripe Checkout, APIs, API/Services Architecture, API Design, GraphQL, Vim Text Editor, Linux, Unix, Socket Programming, Microservices, Microservices Architecture, MySQL, Front-end, Back-end, HTML, CSS

Software Engineer

2012 - 2013
  • Launched a cross-platform mobile development sub-department using Xamarin, yielding substantial profits in the initial months.
  • Designed an abstraction layer for Google Maps integration in Xamarin iOS and Android.
  • Improved the performance and user experience of various mobile apps significantly by implementing concurrent data management.
Technologies: C#.NET, C#, Xamarin, C++, iOS, Android, Windows Phone, Agile, Objective-C, Objective-C++, Git, APIs, MySQL, MySQL Server

Social Network on Blockchain

I joined this project when there was nothing but an idea in the client's head. He wanted to create a new social network where any user could make money right off their personal content.

Such an idea required us to build a system with high security, transparency, and trustfulness. Here, I proposed that blockchain technologies can help us achieve that. I figured out a new concept of working with blockchains and NFTs, which is patented now.

After two months of intense work, I clarified the requirements and business vision, prepared a specification and architecture design for the project, and built a development team for it. We went with microservices and Kubernetes for scaling.

Since I was the most experienced development team member, I took on the most complex tasks. In the meantime, I managed the other three developers, helped them solve issues, and worked with the marketing team to clarify requirements and direction.

This approach allowed us to release the product four months after the start, doing things quickly, not forgetting about best practices such as code quality, documentation, tests, and CI/CD. The system was launched and started to bring income within three months.

Contactless Business Card with Custom Design

During COVID-19 times, my friend and I figured out an idea of a service we could provide for business people and artists in Montreal.

We researched what people are looking for, who competitors are, and what we can offer. We used a progressive web app solution to bypass Google Play and Apple Store limitations and fees and share users' business cards with just a link, which magically converts to an application.

I designed the system's architecture, configured hosting on Google Cloud, and created the back end with Ruby on Rails. In addition, I found and managed a UI designer and several Ionic 4 developers to build the application's front end.

Toptal Platform

For more than five years, I worked as a part of Toptal's core team, contributing to developing and improving an enterprise product. I was surrounded by a large team of top-level developers. I was also a part of a small sub-team of experts whose job was to find and fix performance issues, improve the quality of life for the entire platform, and research paths of potential evolution for it.

I mainly worked with Ruby, digging deep into Rails and several other libraries. My contribution resulted in a significant performance and stability increase, as well as a redesign of several parts of the system.

But it wasn't only about Ruby and Rails—I learned a lot about other technologies and solutions, including Python, Django, Jenkins, Kibana, and Grafana.


Ruby, TypeScript, SQL, JavaScript, GraphQL, C++, ECMAScript (ES6), ES7, C#.NET, C#, Objective-C, Python, Python 3, HTML, CSS3, CSS


Ruby on Rails (RoR), Ionic, Django, Jest, NestJS


GitHub, Vim Text Editor, Git, Slack, NGINX, Jira, Google Kubernetes Engine (GKE), Jenkins, Grafana, Kibana, Stripe Checkout


Object-oriented Programming (OOP), Agile, Test-driven Development (TDD), Microservices Architecture, API Architecture, API/Services Architecture, Microservices, CQRS, Socket Programming, DevOps


Linux, Unix, Docker, Blockchain Platforms, Kubernetes, Google Cloud Platform (GCP), Blockchain, Xamarin, iOS, Android, Windows Phone, Amazon Web Services (AWS), Ethereum, Apache Kafka


Program Development, APIs, OOP Designs, API Integration, Domain-driven Design (DDD), GitFlow, API Design, System Design, CI/CD Pipelines, Data Processing, Customized Blockchains, Non-fungible Tokens (NFT), Scaling, Performance, Debugging, Stripe Payments, Optimization, IT Management, Team Leadership, Remote Team Leadership, Streaming, Objective-C++, Progressive Web Applications (PWA), Ethers.js, Analytics, Research, Stripe Marketplace, CTO, Front-end, Back-end, Full-stack, Global Banking, IT Systems Architecture, Full-stack Development, Third-party APIs, TypeORM, Fintech, Digital Payments, Card Payments, Stripe Subscriptions, Stripe Terminal, Online Banking, Enterprise, Software Architecture, Leadership, Technical Leadership, Social Media Apps, Startups, Architecture


Node.js, Sidekiq, Stripe, Stripe API, REST APIs, Stripe Connect, React, Sockets, GitHub API, Stripe Connect API


PostgreSQL, Redis, MySQL, MongoDB, Elasticsearch, MySQL Server, PostgreSQL 10

2009 - 2014

Engineer's Degree in Computer and Information Sciences and Support Services

Ulyanovsk State Technical University - Ulyanovsk, Russia

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