Piotr Kuczynski
Verified Expert in Engineering
Software Developer
Berlin, Germany
Toptal member since February 19, 2016
Piotr is a highly motivated, proactive, and ambitious software engineer with outstanding technical skills and over 20 years of experience. As an entrepreneurial professional and Agile evangelist, he has a strong personality and experience managing international and distributed teams. Piotr specializes in web development, performance optimization, and architecture design and is interested in usability and slick user interface designs.
Portfolio
Experience
- JavaScript - 20 years
- PostgreSQL - 10 years
- Node.js - 8 years
- React - 6 years
- Google Cloud Platform (GCP) - 5 years
- Amazon Web Services (AWS) - 4 years
- Redux - 4 years
- TypeScript - 1 year
Availability
Preferred Environment
JavaScript, Node.js, React, TypeScript
The most amazing...
...thing I've built was a startup that grew to 50 employees and 20 million members in two years.
Work Experience
Lead Software Engineer
Checkatrade
- Built back-end microservices, formulating the core platform for the new Checkatrade end-to-end offering.
- Designed API standards and a set of REST and AsyncAPI.
- Converted user stories into technical requirements.
- Communicated with all stakeholders and legacy system owners.
- Introduced shared types and SDK packages to speed up the cross-team development process, increase code re-usage, decrease code duplication, and improve overall quality.
- Delivered beta and MVP apps on time despite ultra-tight deadlines.
Senior Software Engineer
Engel & Völkers
- Built a single-page application managing contracts and licensing fees.
- Implemented continuous integration and continuous delivery processes using GitLab.
- Built a REST API as Node.js, TypeScript, and PostgreSQL back end deployed with Docker to a Kubernetes cluster on GCP.
- Hired new team members and supervised less experienced developers.
- Converted business requirements into user stories and software architecture.
Software Architect
Coperniq
- Advised on the software architecture for an MVP project management tool for solar engineering companies.
- Provided consulting services on choosing appropriate technologies and tools.
- Hired new engineers, built the team, and set up processes to deliver the project efficiently.
Senior Software Engineer
InterJoin Ltd
- Played a key role in InterJoin, a startup in the seed phase that was building an online platform to connect people interested in exchanging knowledge and services.
- Built the MVP prototype rapidly from scratch based on the Zeplin designs.
- Developed a single-page application in React using the Next.js framework, partially rendered statically and server-side for SEO optimization.
- Constructed a Node.js back end in TypeScript for the app using MongoDB as a database.
- Integrated a few open APIs for mocking parts of the profile, such as photos, to satisfy the MVP concept in the given limited time.
- Created continuous deployment pipelines using Vercel.
- Advised on UX and UI proposals from the designer who was part of the team.
Lead Software Engineer
COMATCH
- Contributed significantly to an online marketplace that connects companies of all sizes with independent business consultants and industry experts registered in their network for project-based work.
- Built a microservice using TypeScript, which extracts and analyzes text from CVs exported from LinkedIn in PDF format and converts them to machine-readable JSON.
- Established continuous integration processes using CircleCI.
- Configured the deployment using AWS API Gateway and Lambda.
- Led a small team of two back-end software engineers.
Senior Software Engineer
Zalando Lounge Service
- Worked on a Salesforce integration and a content management application for ordering content from agencies.
- Developed various tools supporting marketing activities and data analytics for the marketing tech department.
- Built a single-page application in React, with a Node.js, TypeScript, and PostgreSQL back end, to optimize the process of managing content orders from external agencies, such as product descriptions, landing pages, and SEO.
- Integrated with the agency's 3rd-party APIs and exposed my own API as a webhook to receive agency process notifications.
- Created a service for downloading analytical data daily from App Store Connect, converting it to CSV, and exposing it to the data analytics team in the S3 bucket.
- Developed mass marketing emails using Salesforce Marketing Cloud.
- Handled the deployments and infrastructure management in AWS with Kubernetes.
Senior Software Engineer
Daimler Fleetboard
- Worked on a platform for tracking the geopositioning and truck-trailer coupling status using a mobile app and physical sensors combined with data science algorithms.
- Built a Node.js back end collecting data from various sources, including a mobile app, SOAP Listener, and Azure Event Hubs, persisting it to PostgreSQL and forwarding it to a data science platform.
- Developed a single-page application in Angular 8, displaying the geopositioning and coupling status over the HERE Maps view.
- Handled the deployments and infrastructure management in Azure DevOps and Azure with Kubernetes.
Front-end Lead
Körber Digital
- Led a team of four front-end engineers working on an IoT product.
- Built single-page applications in React that displayed analytical data for a production line and enabled operators to send feedback for machine speed losses.
- Developed the back end in JavaScript-based serverless architecture on AWS.
- Managed deployments and infrastructure in CircleCI and AWS or Azure.
- Hired new team members, including front-end, back-end, and QA engineers.
Senior Software Engineer
GoEuro (now Omio)
- Contributed as part of the fast integrations department for GoEuro, a travel metasearch engine that allows users to compare the price and journey time of air, rail, and bus travel options in a single search.
- Built end-to-end services offered to micro providers, covering search, routing, booking, ticket generation, and sales reporting.
- Developed back-end services in Node.js, including search, routing, and booking, which I implemented in a microservice architecture and deployed to GCP using Kubernetes.
- Implemented a PDF ticket-printing service as a server-side React app in Node.js.
- Managed deployments and infrastructure in Kubernetes.
Senior Software Engineer
SatoshiPay
- Built a drop-in web widget serving as a payment and content management client using React and Redux.
- Migrated from Bitcoin to alternative cryptocurrency providers.
- Implemented new cryptocurrency micropayment services.
Senior Software Engineer | Product Owner
Freelance
- Served as a senior software engineer at SwapDoq and product owner at TravelMind Inc.
- Built from scratch a prototype of a mobile web app based on React for sharing content-rich marketing brochures that include photos, videos, 3D objects, and animations.
- Researched and designed a prototype of a next-generation travel management mobile app providing a seamless booking and time organization experience with a slick and simple user interface.
Senior Software Engineer
Zalando
- Developed Zalando's shop, the main front-end application customers use among many applications and services.
- Built a React component library used across the company to quickly develop new features and maintain consistent UX/UI.
- Applied refreshed UI designs for the main parts of the shopping application.
Senior Product Owner
Smartlaw (owned by Wolters Kluwer)
- Developed new product ideas to increase the user base.
- Refactored an existing functionality to increase conversions.
- Implemented a notification system to bring people back to the site more often.
- Redesigned and improved interactions for a better user experience and increased satisfaction.
- Managed the backlog and prioritized features and bug fixes.
Senior Front-end Software Engineer
smava
- Developed a front-end application using Backbone.js.
- Refactored existing code to achieve greater readability, testability, and performance.
- Converted parts of the site to support responsive design.
- Solved compatibility issues between browsers and platforms.
Product Owner | Technical Lead – Izumi
Here Technologies (formerly a Nokia business)
- Worked on Izumi, an internal crowdsourcing localization tool used by the HERE product family, moving the localization process into the continuous delivery world and shortening translation cycles from three weeks to a few minutes.
- Defined the product scope and technical architecture.
- Managed a small development team in Berlin, Germany, and Atlanta, USA.
- Developed a full stack in Ruby on Rails with MySQL, HTML5, Sass, and JavaScript.
- Introduced crowdsourced localization to the company.
- Changed the localization process from a highly manual job to a fully automated process.
- Shortened localization cycles from a few weeks to a few minutes.
Product Owner | Technical Lead – Dashboard
Here Technologies (formerly a Nokia business)
- Developed the analytics dashboard displaying major KPIs for various Nokia products and services.
- Handled product definition, design, and development.
- Led the development and delivery team of three engineers.
- Increased team engagement significantly and improved work quality and results by applying my expertise in product KPIs.
Senior Development Manager
Here Technologies (formerly a Nokia business)
- Enhanced front-end performance by reducing the web page loading time from 30 to less than six seconds.
- Improved cross-team cooperation by implementing continuous integration processes and running weekly tech talks, where developers could freely exchange knowledge.
- Optimized the build system and overall release process—from every few months to only three weeks. Shortened the time from development to release by deploying it to production at the end of each sprint.
- Increased Google indexing from thousands to millions of pages by designing and implementing an SEO strategy to boost presence on Google.
- Mentored a web front-end development team of 28 developers.
- Oversaw the overall Nokia Maps architecture for the web.
- Led the integration with other Nokia and HERE services.
- Worked on new product development and ideas with business owners and the UX team.
Development Manager
Wayn
- Hired and managed a development team of 12 developers and three testers, helping build the Polish branch office's unique, friendly atmosphere.
- Managed the workflow to maintain a dynamic development process, ensuring the website's quick growth.
- Authored most of the website's core back-end mechanisms and provided expertise in database optimization.
- Led the development process and wrote the most crucial part of the system.
Director of Research and Development
Wayn
- Solved the crucial performance issues of the website by clustering the back-end database.
- Improved the core template processing mechanism, which sped up the development process.
- Prepared the website for a multilingual interface.
- Increased website traffic significantly by redesigning the website interface, which company members and the industry warmly welcomed.
- Hired and led a development team of 16 developers and seven testers and an R&D team of two application architects and three graphic designers.
- Mentored and helped individuals to achieve their goals.
- Worked with partners on various product integrations, including global SIM cards, geolocation service, white labeling, branded credit cards, and hotel or restaurant booking.
Owner | Network Administrator
HYPODE Networks
- Started HYPODE Networks to provide part-time network administration services.
- Built and managed a local computer network infrastructure.
- Provided over 50 clients with internet access and services like email accounts and personal website hosting.
Senior Software Engineer | Team Leader
Mole Resourcing Ltd
- Developed the website's first version based on business owners' specifications.
- Built and managed a team of three developers and one graphic designer.
- Managed the build, deployment, and testing processes.
Senior Software Engineer
Wayn
- Joined as one of the first two developers and was a co-author of the core website mechanisms.
- Built the "invitation via contact import" mechanism, which allowed the website to grow from 45,000 to 1.5+ million members within six months and later maintain that growth.
- Developed a web-based instant messenger, written using pure HTML and JavaScript—one of the first worldwide—working almost unchanged until today.
Senior Software Engineer
Heuthes
- Designed an advanced client-side template processing mechanism that separated the visualization layer from the data stream and business logic.
- Built the solution using advanced JavaScript and Ajax and rendered it in browsers using XML and XSL. This improved the development process and application performance via better caching and decreased data transmission requirements.
- Developed the web-based business management system using advanced JavaScript, HTML, and HDB, a scripting language invented internally by the company, written in Delphi and running on Windows and Linux.
- Prepared technical documentation in Polish and English for the web-based banking products developed by the company Filia@Web and Virtual Info Banking.
Teacher
Maius College
- Gave lectures and led laboratory classes on the subject of databases.
- Taught relational databases and SQL language based on the PostgreSQL database system.
- Engaged as a part-time teacher in the College of Economics and Information Technology while employed as a full-time teacher at Szczecin University of Technology.
Teacher
Szczecin University of Technology
- Used the modern RDBM system to teach SQL, which required organizing a dedicated server running PostgreSQL for the students' databases.
- Organized and led a group of students interested in software development. They participated in a contest for the best application written in Java for the Nokia Communicator 92xx platform organized by Borland Poland.
- Introduced HTML and JavaScript classes in the Introduction to Computer Science course.
- Taught first-year Computer Science studies to Bachelor of Science students before finishing my master's degree.
Software Engineer | Blogger
Freelance
- Developed the 2nd version of an application for Visuell Kommunikation AB in cooperation with the product manager from Sweden.
- Fostered and maintained "Delphi in Questions & Answers"—the biggest Polish website at the time about Borland Delphi—as the creator and main contributor.
- Served as the animator of the community associated with Delphi and internet newsgroups.
Experience
InterJoin Ltd
Zalando Lounge
Daimler Fleetboard
https://www.fleetboard.infoI worked on a platform that tracks the geopositioning and truck-trailer coupling status using a mobile app and physical sensors combined with data science algorithms. My responsibilities included building a back end in Node.js to collect data from various sources and a single-page application in Angular to display the data over the map view.
Körber Digital
https://www.koerber-digital.comGoEuro (now Omio)
SatoshiPay
https://www.satoshipay.ioZalando Shop
http://zalando.comSmava
https://www.smava.deSince its launch in 2007, more than 15,000 investors and 6,000 borrowers have done business with each other through the smava.de credit market, with loans totaling around €55 million in value.
SmartLaw
https://www.smartlaw.deSmartLaw revolutionizes the creation of contracts and other legal documents. To deliver simple, cost-effective, and individualized documents, we combine the strengths of innovative software with expert lawyers and leaders in their fields. Each document is adapted to the user's personal needs, whether a large enterprise, small business, or private individual.
They work exclusively with top-ranked lawyers, and renowned communication designers have developed the platform's user interface and intuitive design. Data protection and security also fulfill the highest certification standards.
HERE Platform
https://www.here.comWAYN.com
ISOF ERP
http://www.isof.plCOMATCH (Malt)
Ruby Version Manager
https://rvm.ioFaker.js
https://fakerjs.devRuby Configuration
https://github.com/rubyconfig/configCheckatrade Consumer App
Education
Postgraduate Degree in Pedagogy
Szczecin University of Technology - Szczecin, Poland
Master of Science Degree in Information Technology
Szczecin University of Technology - Szczecin, Poland
Certifications
The Enterprise Lean Startup Survival Guide
Udemy
Certified Scrum Product Owner
Scrum Alliance
Skills
Libraries/APIs
jQuery, React, Node.js, React-Intl, Chai, REST APIs, Puppeteer, D3.js, Yup, Playwright, React Testing Library, Backbone.js, Windows API, Sinon.JS, NgRx, RxJS, Protobuf, Winston, Formik
Tools
NPM, Webpack, GitHub, Git, Jira, CircleCI, Travis CI, Sentry, GitLab CI/CD, GitLab, Cucumber, Salesforce Marketing Cloud, Keycloak, Grafana, InVision, Moqups, Amazon CloudFront CDN, Apache Maven, Hudson, Jetty, Apache Tomcat, Apache, Mocha, Zeplin, Karma, Stellar SDK, GIS, Kibana, Terraform, Helm, Litmus
Languages
Object-oriented JavaScript (OOJS), HTML, CSS, Visual Basic 6 (VB6), XML, HTML5, CSS3, JavaScript, Sass, TypeScript, SCSS, SQL, Bash, Ruby, T-SQL (Transact-SQL), Java, PHP, Delphi, dBASE, UML, Visual Basic for Applications (VBA), XSL, XPath, Less, C++
Frameworks
Next.js, Redux, Jest, Koa, Express.js, JSON Web Tokens (JWT), OAuth 2, Fastify, Ruby on Rails (RoR), Cypress, Material UI, Bootstrap, Grails, Selenium, JBehave, Jasmine, JUnit, Jakarta Server Pages (JSP), Angular
Paradigms
Serverless Architecture, Scrum, Kanban, Test-driven Development (TDD), Unit Testing, E2E Testing, B2B, Agile Project Management, Agile, Requirements Analysis, Azure DevOps
Storage
MySQL, PostgreSQL, Google Cloud Storage, Google Cloud SQL, RDBMS, SQL Server Reporting Services (SSRS), Microsoft SQL Server, Amazon S3 (AWS S3), MongoDB, Redis, Docker Cloud, Datadog
Platforms
Amazon EC2, Amazon Web Services (AWS), Ubuntu, Linux, Docker, Kubernetes, AWS Lambda, Google Cloud Platform (GCP), Salesforce, Amazon, Nexus, Vercel, Azure, Mailgun, Desktop, Firebase, Blockchain
Other
Serverless, Scraping, Cloud Architecture, TypeORM, CSS Modules, Storybook, Full-stack Development, CTO, Front-end Development, Front-end, Web Applications, APIs, User Interface (UI), Google Pub/Sub, ESLint, i18n, IT Project Management, Software Architecture, Lean Project Management, Project Consultancy, Certified Scrum Product Owner (CSPO), Software Development Management, Engineering, Delivery Management, Engineering Management, People Management, Team Management, Architecture, Leadership, Full-stack, Authentication, SDK Development, SDKs, Front-end Architecture, Front-end Design, Back-end Development, Large-scale Projects, Pub/Sub, Gatsby, LDAP, Amazon API Gateway, GitHub Actions, WebSockets, General Transit Feed Specification (GTFS), eCommerce, Cryptography, User Experience (UX), Pedagogy, Technical Writing, PDF, Web Security, Maps, Amazon Route 53, Enzyme, Bitcoin, IOTA, Cryptocurrency, HTML Email, Prometheus, SAP Business ByDesign, SAP, Software Engineering, Computer Science, OpenID Connect (OIDC), GetStream, OpenStreetMap, Routing, App Store Connect, Cryptocurrency Wallets
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