Michał is available for hire
Hire MichałMichał Kijowski
Verified Expert in Engineering
Back-end Developer
Warsaw, Poland
Toptal member since May 4, 2016
Bio
Michał is an accomplished full-stack software engineer known for leading complex integration projects and creating innovative applications. His experience ranges from early-stage startups to major platforms, with deep expertise in technologies such as TypeScript, Node.js, React, MySQL, and cloud services, including AWS and GCP. Michał excels in enhancing algorithm performance and devising statistical models, showcasing his capability to innovate and solve problems in dynamic settings.
Portfolio
Winware
TypeScript, JavaScript, Node.js, Google Cloud Platform (GCP), MySQL...
UserZoom
TypeScript, Node.js, React, Express.js, WebRTC, JavaScript, WebSockets...
UserZoom
TypeScript, Node.js, React, Redux, WebRTC, WebSockets...
Experience
- Back-end - 10 years
- Algorithms - 7 years
- JavaScript - 7 years
- WebRTC - 7 years
- TypeScript - 7 years
- Node.js - 7 years
- React - 6 years
- SQL - 5 years
Availability
Part-time
Preferred Environment
Git, Node.js, TypeScript, JavaScript, React, Redux, Linux, Bash, WebRTC, WebSockets
The most amazing...
...project I've led was the development of a remote moderated UX testing tool, significantly improving user experience research capabilities for global clients.
Work Experience
Software Engineer
2022 - 2023
Winware
- Enhanced core algorithm efficiency, reducing calculation times by tenfold and optimizing performance in a high-stakes startup environment.
- Developed a novel statistical model to evaluate user health through in-app action analysis, pioneering new user engagement and retention avenues.
- Played a pivotal role in shaping the company's technical direction, leveraging deep technical expertise to guide strategic decisions and technology adoption.
Technologies: TypeScript, JavaScript, Node.js, Google Cloud Platform (GCP), MySQL, Google BigQuery, Data Engineering, Algorithms, Machine Learning, Test-driven Development (TDD), SQL, Git, Visual Studio Code (VS Code), Data Structures, Computer Science, Data Mining, Linux, Bash, Statistics, Express.js, Docker, Back-end, Full-stack
Lead Software Engineer
2020 - 2022
UserZoom
- Oversaw the continuous improvement and maintenance of a remote moderated UX testing tool, ensuring high performance and user satisfaction.
- Led the successful internationalization of the application, enabling global accessibility and enhancing user experience across diverse markets.
- Directed a strategic recruitment drive that led to hiring a key developer, significantly boosting the team's productivity and project outcomes.
Technologies: TypeScript, Node.js, React, Express.js, WebRTC, JavaScript, WebSockets, Amazon Web Services (AWS), Google Cloud Platform (GCP), Algorithms, Test-driven Development (TDD), SQL, Git, Scrum, Visual Studio Code (VS Code), Data Structures, Computer Science, Front-end, Continuous Integration (CI), Linux, Bash, Docker, MySQL, User Experience (UX), CSS, Back-end, Full-stack, React Query
Senior Software Engineer
2019 - 2020
UserZoom
- Led the integration of Validately's moderated UX solution into the UserZoom platform, enhancing the solution's reach and functionality across two distinct platforms.
- Engineered robust solutions to merge disparate systems, involving complex data migrations and API integrations while minimizing downtime and user impact.
- Utilized GCP and AWS cloud services to scale the integrated platform efficiently, achieving higher availability and resilience.
Technologies: TypeScript, Node.js, React, Redux, WebRTC, WebSockets, Google Cloud Platform (GCP), Amazon Web Services (AWS), JavaScript, Algorithms, Test-driven Development (TDD), SQL, Git, Scrum, Visual Studio Code (VS Code), Data Structures, Computer Science, Front-end, Continuous Integration (CI), Linux, Bash, Express.js, Docker, MySQL, User Experience (UX), CSS, Back-end, Full-stack
Software Developer
2016 - 2019
Validately
- Developed a remote moderated UX testing tool using TypeScript, incorporating a React-based front end, Express/Socket.io back end, and a Google Chrome extension, which significantly increased client engagement and feedback precision.
- Designed and implemented an unmoderated UX testing tool with screen recording features, broadening the usability testing capabilities for clients.
- Created an internal logic routing system and an admin dashboard, optimizing operations and project management efficiency.
Technologies: TypeScript, Node.js, JavaScript, WebRTC, Express.js, WebSockets, Google Cloud Platform (GCP), Docker, MySQL, React, Redux, Algorithms, Test-driven Development (TDD), SQL, Git, Scrum, Visual Studio Code (VS Code), Data Structures, Computer Science, Front-end, Linux, Bash, User Experience (UX), CSS, Back-end, Full-stack
Software Developer
2013 - 2015
Orbis Investment Advisory Limited
- Designed a ReactiveX and dataflow programming-based tool for alpha model analysis and backtesting. The tool became the go-to research tool for analysts.
- Developed a C# tool with WPF UI and WCF service for portfolio cash flow management, simplifying PMs' daily workflows. Served as the main implementer in a team of three.
- Implemented a market research tool for theme performance analysis with complex criteria in a team of five, including developers, a data analyst, and a PM.
- Verified and optimized multiple financial models created by quantitative analysts in SQL, MATLAB, and R.
- Provided support for legacy software developed mostly in Visual Basic 6 and SQL.
Technologies: MATLAB, T-SQL (Transact-SQL), F#, C#, Algorithms, Machine Learning, Test-driven Development (TDD), SQL, Microsoft Visual Studio, SQL Management Studio, Microsoft SQL Server, Scrum, Data Structures, Computer Science, Data Mining, Continuous Integration (CI), Financial Data, Financial Modeling, Dataflow Programming, Statistics, Data Engineering, Investments, Back-end
Software Developer
2010 - 2012
University of Warsaw, Faculty of Mathematics, Informatics, and Mechanics
- Contributed to the Synat Research Project, a strategic program funded by the National Research and Development Center.
- Created an innovative semantic faceted search engine as a part of my master's degree thesis. It was developed in Python and C# with a PostgreSQL database.
- Co-authored the relational database schema aimed at efficient storage and querying parsed scientific articles.
- Worked on collecting, parsing, and preprocessing of scientific data from various sources.
Technologies: Mercurial, PostgreSQL, Python, C#, Machine Learning, SQL, R, Computer Science, Natural Language Processing (NLP), Data Engineering, Back-end
Experience
Kinesis Advantage2 Remapping Helper
http://kinesis.vercel.appThe Kinesis Advantage2 Remapping Helper is an intuitive web-based tool designed specifically for owners of the Kinesis Advantage2 keyboard.
This utility simplifies the process of visualizing and editing remap files, making it easier for users to customize their keyboard layout to suit their personal or professional needs. By entering key remaps and macros into the provided text area, users can instantly see their updated keybindings displayed on a virtual keyboard layout.
Additionally, the tool parses and lists all recognizable macros, offering a comprehensive overview of custom configurations.
This utility simplifies the process of visualizing and editing remap files, making it easier for users to customize their keyboard layout to suit their personal or professional needs. By entering key remaps and macros into the provided text area, users can instantly see their updated keybindings displayed on a virtual keyboard layout.
Additionally, the tool parses and lists all recognizable macros, offering a comprehensive overview of custom configurations.
mkswap
https://mkswap.vercel.appAccording to the famous psychology paper "The Magical Number Seven, Plus or Minus Two," we are able to hold between five and nine pieces of information in our short-term memory.
mkswap is a simple tool that was designed to help with the overload of said memory by creating a place where you can quickly capture short-lived pieces of information. It simulates the higher end of the bell curve and can hold nine pieces of information.
Adding a new item after you reach the limit will delete the oldest item in the list. Adding new items pushes older ones closer to oblivion. Your list is cached for the duration of your browser session.
mkswap is a simple tool that was designed to help with the overload of said memory by creating a place where you can quickly capture short-lived pieces of information. It simulates the higher end of the bell curve and can hold nine pieces of information.
Adding a new item after you reach the limit will delete the oldest item in the list. Adding new items pushes older ones closer to oblivion. Your list is cached for the duration of your browser session.
RDBMS Model for Scientific Articles Analytics
The relational database schema that I co-authored. It aimed at efficient storage and querying parsed scientific articles. This database was described in the article published in the book titled "Intelligent Tools for Building a Scientific Information Platform."
Education
2011 - 2016
Master's Degree in Computer Science
University of Warsaw - Warsaw, Poland
2010 - 2013
Master's Degree in Mathematics
University of Warsaw - Warsaw, Poland
2007 - 2010
Bachelor's Degree in Mathematics
University of Warsaw - Warsaw, Poland
Certifications
JUNE 2020 - PRESENT
UserZoom Core Certification
UserZoom
JANUARY 2015 - PRESENT
Claritas® Investment Certificate
CFA Institute
Skills
Libraries/APIs
Node.js, React, WebRTC, React Query
Tools
Git, Microsoft Visual Studio, PostCSS, Mercurial, MATLAB, SQL Management Studio
Languages
TypeScript, JavaScript, SQL, R, T-SQL (Transact-SQL), C#, F#, Bash, CSS, Python
Frameworks
Redux, Express.js, Next.js, Tailwind CSS, Mithril.js
Paradigms
Scrum, Continuous Integration (CI), Test-driven Development (TDD), Dataflow Programming, Compiler Design
Platforms
Visual Studio Code (VS Code), Linux, Docker, Google Cloud Platform (GCP), Amazon Web Services (AWS), Vercel
Storage
MySQL, Microsoft SQL Server, PostgreSQL
Other
Algorithms, Data Structures, Computer Science, Front-end, WebSockets, User Experience (UX), Back-end, Full-stack, Machine Learning, Data Mining, Natural Language Processing (NLP), Statistics, Combinatorics, Data Engineering, Financial Data, Financial Modeling, Optimization, Google BigQuery, Investments
Collaboration That Works
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
1
Share your needs
Discuss your requirements and refine your scope in a call with a Toptal domain expert.
2
Choose your talent
Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.
3
Start your risk-free talent trial
Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.
Top talent is in high demand.
Start hiring