Lukasz Reszczynski
Verified Expert in Engineering
Full-stack Developer
Umeå, Sweden
Toptal member since September 21, 2020
Lukasz is a UK-educated full-stack web application developer who has authored papers and patents in his field. Trained in computational astrophysics and bioinformatics, he has over a decade of experience developing enterprise software applications. All in all, Lukasz excels at turning a client's vision into reality.
Portfolio
Experience
- PHP - 15 years
- JavaScript - 15 years
- MySQL - 15 years
- React - 5 years
- Apache Solr - 5 years
- PHP 7 - 5 years
- Docker - 3 years
- Laravel - 1 year
Work Experience
Co-founder
Pango Solutions AB
- Developed an embedded Shopify app for handling returns and exchanges https://apps.shopify.com/pango.
- Implemented integrations with last-mile delivery carriers.
- Implemented innovative AI product inspection mechanisms and peer-to-peer routing of returns.
Developer | Contractor
Shopify Plus merchant (via Toptal)
- Developed a custom payment capture and order fulfillment mechanism interacting with Shopify API and payment gateways, reducing order fulfillment time by 95% to under five seconds for a high-traffic store selling digital products.
- Implemented custom fraud checking routines, reducing revenue lost to fraud.
- Facilitated migration to Shopify's checkout extensibility.
Mobile App Developer | Contractor
Weaver Dating Inc.
- Developed a React Native mobile application for iOS and Android.
- Created a back-end API in Node.js (Express.js) for the mobile application.
- Built and implemented a matching algorithm utilizing Apache Solr.
Developer | Contractor
US-based biotechnology company (via Toptal)
- Created a desktop application, implementing a novel algorithm recently published by a collaborator. Worked as part of a team of scientists and engineers at a biotechnology startup.
- Used Electron and Python to develop a production-ready, multiplatform desktop application based on research code written in MATLAB.
- Developed production-level software for recognition, statistical analysis, and visualization of biological cell ensembles from a time series of microscopy images, using image processing techniques, particularly optical flow analysis.
Developer (Consultant)
Partfiniti, Inc.
- Provided technical guidance and facilitated the development transition of a web application that I had previously built for an outsourcing team.
- Containerized the application using Docker and created automation using Ansible for bringing up deployment environments.
- Undertook research and development to improve key product features.
- Refactored an extensive legacy front-end codebase built on jQuery into a hierarchy of reusable components using React's 1-way data flow paradigm.
Guest Researcher, Marie Curie ESR
Medical University of Vienna
- Performed numerical simulations that shed light on the nature of phylogenetic quasi-terraces. Co-authored a paper: Biorxiv.org/content/biorxiv/early/2019/10/18/810309.full.pdf.
- Integrated a Terraphast library written in C into the popular phylogenetic package IQ-TREE. Acknowledged in the following paper: Academic.oup.com/mbe/article/37/5/1530/5721363.
- Conducted numerical simulations and designed algorithms in the service of investigating phylogenetic terraces.
Lead Developer
Partfiniti, Inc.
- Led the development of a greenfield SaaS ERP product to create a platform connecting fiber optics part manufacturers, vendors, and buyers.
- Created a novel part configurator, bill of materials, and quoting tool that has since been used to quote products worth over $1,5 billion.
- Invented and deployed a production implementation of a fiber optics part configurator. It qualitatively increased the product’s capabilities while lowering infrastructure costs. Patented as Patents.google.com/patent/US10121177B2.
- Passed on the ongoing maintenance and operations of the product to an outsourcing company.
Lead Developer
JobRefer, Inc.
- Joined as a front-end developer and took over the lead position at a San Francisco-based startup.
- Built a small development team in Warsaw and led the development of B2B social recruiting web application.
- Created a single-page application (SPA) front end for the web application.
Web Developer
Mikroproject
- Maintained the legacy code and developed new features for internal and external projects.
- Designed database schemas and developed an ORM-like collections library to supplement Zend Framework's database management features.
- Gathered requirements from clients and non-technical team members.
Web Developer
Hexlabs Ltd
- Maintained and developed new features for the company’s flagship product, Fusedworld.com—an international real estate directory.
- Maintained and developed new features for a complex customer relationship management (CRM) application.
- Provided technical support for enterprise clients.
Project History
Pango | Return and Exchange Management for Shopify Merchants
https://apps.shopify.com/pangoWeaver Dating
Partinator
https://www.partfiniti.com/partinator/I designed the underlying algorithm, implemented and deployed a production version in the form of a web application integrated with a bill of materials (BOM) and quoting tools.
Patented as https://patents.google.com/patent/US20190043108A1.
Admission Report
https://www.admissionreport.comTechnically, it features an advanced pipeline for collecting, cleaning, and processing admissions information from many heterogeneous sources.
Playlist Hunter
In addition to the core feature of allowing aspiring music producers to contact the relevant playlist curators, it can manage application feature subscriptions, calculate VAT, generate invoices, and has a GDPR-compliant control panel based on Laravel Voyager.
The back end is written in PHP on top of the Laravel framework and exposed to the front end as a REST API.
Education
Bachelor's Degree in Molecular Biology and Chemistry
Umeå University - Umeå, Sweden
Doctor of Philosophy (Unfinished) in Molecular Biology | Bioinformatics
University of Vienna - Vienna, Austria
Master of Science (Distinction) in Astrophysics
Liverpool John Moores University - Astrophysics Research Institute, Liverpool, United Kingdom
Bachelor of Science (First Class Honors) in Applied Mathematics and Physics
The Open University - Milton Keynes, United Kingdom
Certifications
PHP5 Zend Certified Engineer
Zend Technologies
Skills
Libraries/APIs
React, jQuery, REST APIs, LinkedIn API, Node.js, Facebook API, X (formerly Twitter) API, Google Analytics API, NumPy, SciPy, Stripe, Stripe API, Vue, Python API, Laravel Voyager, OpenCV, Shopify API, OpenAI API, Playwright, UPS API
Tools
Apache Solr, Ansible, Apache, FullStory, RabbitMQ, PhpStorm, Git, Composer, Ansible Tower, Stripe Checkout, GitHub, Webpack, NPM, Docker Compose, Jenkins, PyInstaller, MATLAB, Sequelize, Shopify Plus, Astro, Integrative Genomics Viewer (IGV)
Languages
PHP, PHP 5, PHP 7, JavaScript, HTML, HTML5, CSS, SQL, Python, C++, C, Transact-SQL (T-SQL), TypeScript, PHP 8, R
Frameworks
Zend Framework, Laravel, React Native, Symfony, Ext JS, Bootstrap, Selenium, Electron, Express.js, Redux, Flask
Platforms
LAMP, iOS, Docker, Apache2, Firebase, Google Cloud Platform (GCP), Android, MacOS, Ubuntu, Amazon Web Services (AWS), Azure, Linode, Heroku, Shopify
Storage
MySQL, Databases, Redis, PostgreSQL, Phinx, MongoDB, Amazon S3 (AWS S3), JSON, Google Cloud
Paradigms
Search Engine Optimization (SEO), DevOps, Continuous Deployment, Unit Testing, Functional Testing
Industry Expertise
Bioinformatics
Other
APIs, Web Scraping, Full-stack, Mobile App Development, Mobile Applications, API Integration, Writing & Editing, Search Engines, Leadership, Applied Mathematics, Mathematics, Computational Biology, Combinatorics, Physics, Computational Physics, Numerical Modeling, Numerical Simulations, Data Visualization, Graphs, Algorithms, Back-end, Architecture, Ajax, Cloudflare, Data Scraping, Responsive Web Apps, Single-page Applications (SPAs), Google Play Store, Command-line Interface (CLI), General Relativity, Quantum Field Theory, Electrodynamics, Computer Vision, Computer Vision Algorithms, Molecular Biology, Chemistry, Organic Chemistry, Medicinal Chemistry, Klarna, OpenAI, Genomics, Sequence Alignment
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