Alex Sidorov, Developer in Ottawa, ON, Canada
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Alex Sidorov

Verified Expert  in Engineering

Software Developer

Ottawa, ON, Canada
Toptal Member Since
June 18, 2014

Alex has experience building complex distributed heterogeneous systems on PHP, Java, Angular, and Ionic. He has project management skills within the framework of Agile methodologies and is confident in forming the optimal technology landscape suited to business challenges.


PostgreSQL, OAuth 2, TypeScript, React, Spring, Google Kubernetes Engine (GKE)...
TopTal & DotAlign Inc.
Test-driven Development (TDD), OAuth 2, TypeScript, React
Toptal & AR / Computer Vision company
React, TypeScript, Node.js, AWS Lambda, React Native




Preferred Environment

Ubuntu Server, MacOS

The most amazing...

...thing I've created is a distributed cloud application with event sourcing architecture, as well as multiple React applications.

Work Experience

Tech Lead | Full-stack Developer

2020 - 2020
  • Built flexible and scalable architecture upon the client's request. Led the solution selection through event sourcing with Axon Framework, scalable architecture with CQRS, and Domain-driven Design and implementing complex logic in Aggregates.
  • Implemented GraphQL API based on Expedia Kotlin GraphQL. Used Project Reactor to implement reactive streams such as Mono or Flux and expose these as GraphQL subscriptions.
  • Integrated Keycloak security layer with React application. Implemented REST API webhooks receiving admin and user events from Keycloak and reflecting it in the Event Sourcing bus. Customized Keycloak to issue Hasura-compatible JWT.
  • Implemented multiple third-party integrations, such as stripe integration for payments, calendar API integration with an additional abstract layer implementing Google and Microsoft Outlook calendars, and Amazon SES as a mail gateway.
  • Configured Kubernetes GKE cluster and Google Build for CI/CD pipelines.
Technologies: PostgreSQL, OAuth 2, TypeScript, React, Spring, Google Kubernetes Engine (GKE), Kubernetes, Event Sourcing, Axon Framework, REST, GraphQL, React Apollo, Kotlin, Java

Senior Software Engineer

2019 - 2020
TopTal & DotAlign Inc.
  • Implemented OAuth 2 authorization and security integration with Azure AD.
  • Implemented responsive layout for a number of internal pages and menus.
  • Controlled REST-API back end contract through unit tests and isolated data transformation layer.
  • Implemented a number of reusable components for similar tables with extended functionality.
Technologies: Test-driven Development (TDD), OAuth 2, TypeScript, React

React Native Developer

2018 - 2018
Toptal & AR / Computer Vision company
  • Developed a number of Node.js AWS Lambdas to collect data from phone sensors for ML algorithms and store in AWS S3.
  • Implemented and published an Android application for collecting camera shots for Computer Vision neural network.
  • Integrated AWS lambda REST API with React Native application.
Technologies: React, TypeScript, Node.js, AWS Lambda, React Native

Senior JavaScript Developer

2016 - 2018
TopTal & LFMX
  • Architected Angular2 application for bespoke accounting frontend software. Had implemented more than 15 various financial document types.
  • Implemented Angular and Redux state management for performance optimization.
  • Visualized dashboard with accrual and cash basis calculations. Implemented company cash flow projection dashboard.
  • Integrated JWT based security guards to manage multi-role access levels for various features.
  • Implemented a simplified customer view to track bills and invoices through the joint library for different Angular2 apps.
Technologies: Kubernetes, OAuth 2, Redux, Redux-observable, RxJS, TypeScript, Angular

Founder | Architect

2011 - 2018
Clever Web LLC
  • Developed service-oriented architecture (SOA) according to client requirements.
  • Served as a high coding standard evangelist for TDD, BDD, and Backbone.js.
  • Created a B2B web application for estate builders and realtors as a lean startup entrepreneur.
  • Developed a reverse proxy Varnish layer for a Symfony2 application. Sped up response time twentyfold.
  • Architected back-end clustering for a dating platform.
Technologies: PostgreSQL, Amazon Web Services (AWS), Elasticsearch, Marionette.js, Backbone.js, Vagrant, Redis, Git, Symfony, MySQL, PHP, Angular, Spring, REST APIs, HATEOAS

PHP/JavaScript Senior Developer, Team Member

2009 - 2011
  • Created various functionality based on Symfony 1.4.
  • Enhanced a periodic billing system.
  • Configured static data storage based on Amazon AWS storing around 6 million customer HD photos.
  • Developed a custom forum with long threads.
  • Supported a project with 70K unique users per day. Optimized performance issues.
Technologies: JavaScript, jQuery, Git, Memcached, Redis, Symfony, MySQL, PHP

Architect | Senior PHP Developer

2007 - 2009
Money4intellect, Ltd.
  • Built a quiz game with synchronized multiplayer gameplay.
  • Created a PHP daemon.
  • Prototyped jQuery AJAX to match requirements.
Technologies: JavaScript, Subversion (SVN), jQuery, Memcached, MySQL, PHP

Team Lead

2006 - 2007
Concern Energomera
  • Led the support team.
  • Supported a financially crucial manufacturing process for the plant of Concern Energomera.
  • Developed a group conference application based on Flash technology.
Technologies: Flash ActionScript, Microsoft SQL Server, MySQL, PHP

PHP Developer

2004 - 2006
Mobil Ug, Ltd.
  • Administered a Linux-based infrastructure.
  • Implemented SMSC socket exchange between the mobile operator, consumer, and service provider.
  • Architected a web-based B2B and B2C application.
  • Created a PHP daemon.
Technologies: Sockets, B2C, B2B, Linux, MySQL, PHP
A wedding portal for brides.


A custom eCommerce solution based on the Symfony2 framework.

Direct Result

A corporate portal maintaining company's operational business processes.

Capital Engines

Wealth Management FinTech project. I participated in interface development.


A B2B web application for estate builders and realtors.

Online Appointment Platform - Klientino

I led this project and participated as hands-on developer. We implemented various web apps (Vue and Angular) and React Native mobile application. The backend uses Java Spring. CI/CD uses Jenkins and Helm with Kubernetes for deployment and Dockerization management.

Deep Walk

A project for a Toptal client. I implemented a mobile application collecting data for a computer vision back end. I used React Native and AWS Lambda.

Bookkeeping System

A large project (12+ months' worth of full-time development) completed for a Toptal client. It was a niche product for a lawyer-focused bookkeeping firm. I participated as team member on the front end and helped with CI/server setup, using AngularJS and Angular, Node.js, Kubernetes, and Jenkins.


GraphQL, JavaScript, TypeScript 3, Java, PHP, Flash ActionScript, Kotlin, TypeScript


Spring, AngularJS, Spring MVC, Angular, React Native, Redux, Symfony, Axon Framework, OAuth 2, Spring Boot, Jest


REST APIs, Spring REST, React, jQuery, Marionette.js, Sockets, RxJS, Backbone.js, Node.js


Service-oriented Architecture (SOA), REST, Dependency Injection, Agile Software Development, Test-driven Development (TDD), Model View Controller (MVC), B2B, B2C, Event Sourcing, Behavior-driven Development (BDD)


Kubernetes, Docker, MacOS, AWS Lambda, Amazon Web Services (AWS), Linux


PostgreSQL, Spring Data JPA, MySQL, Amazon S3 (AWS S3), Elasticsearch, Microsoft SQL Server, MongoDB, Redis, Memcached


Helm, Subversion (SVN), Git, Vagrant, React Apollo, Google Kubernetes Engine (GKE), NGINX


HATEOAS, Ubuntu Server, Redux-observable

1999 - 2004

Master's Degree in Radio Engineering

Taganrog State University of Radio Engineering - Taganrog, Russia


CS50 Mobile App Development with React Native

Harvard University


PSPOI: Professional Scrum Product Owner


LFS158x: Introduction to Kubernetes

The Linux Foundation


SensioLabs Certified Symfony Developer

Pearson Vue

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