Maciej Karpicz, Developer in Torun, Poland
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Maciej Karpicz

Verified Expert  in Engineering

Software Developer

Torun, Poland
Toptal Member Since
May 4, 2018

Maciej is an automation enthusiast who's borderline obsessed with efficiency. Along with his dedication to his craft, he possesses strong analytics and a business-minded approach. As a manager and developer, he delivered projects ranging from small web apps to heavy computer vision-based solutions in healthcare, finance, eCommerce, and education.


Toptal Client
Python, Django, Rust, Stripe API, Pytest, TypeScript, Software Architecture...
Management, Flask-RESTful, Flask, CircleCI, Software Architecture, Celery...
For Days, Inc
Python, Flask, React, Django, Stripe API, Git, JavaScript, GitHub, PyCharm...




Preferred Environment

Git, OS X, PyCharm

The most amazing...

...discovery I've made was learning about probability theory, which shaped my career and my later view on programming and science.

Work Experience

Django/Python Developer

2022 - 2023
Toptal Client
  • Developed a balanced management system and connected payment providers such as Stripe.
  • Integrated one of the KYC providers into the platform, which was one of the key factors in getting clearance from Circle Pay to launch it on the platform.
  • Helped with delivering the platform MVP within a tight deadline.
Technologies: Python, Django, Rust, Stripe API, Pytest, TypeScript, Software Architecture, NGINX


2015 - 2020
  • Cooperated closely with clients during a customer discovery phase, gathering business requirements and transforming them into dev, ML, and DS teams' objectives.
  • Focused on identifying real business needs and translating them into specific actions. Chose the tech stack, designed road maps, and scoped work within the projects' budget and resources.
  • Scoped machine learning-based projects for the company's clients. Based on that work, over 25 projects were delivered as proof of concept of fully working production systems.
  • Designed the architecture along with data pipelines of a web app (based on Django) that simplifies tax settlement processes in Germany. The app used Computer Vision to reduce the time of a single statement preparation statement from 30 to 5 minutes.
  • Planned the architecture and worked as a part of the development team that implemented the web ad auditing engine that could efficiently handle incoming traffic of over 6,000 requests per second.
  • Worked as part of the team that implemented features for a large eCommerce website, including the coupons system, referrals program, and a home delivery system.
  • Built and coached a team of developers and machine learning engineers. Designed career paths and evaluation processes that supported further growth of team members.
Technologies: Management, Flask-RESTful, Flask, CircleCI, Software Architecture, Celery, RabbitMQ, Redis, Amazon Rekognition, GitHub, GitLab CI/CD, Bitbucket, Continuous Integration (CI), Git, HTML5, Customer Discovery, Business Analysis, Confluence, Jira, Docker Compose, MLflow, React, Amazon EC2, Amazon S3 (AWS S3), Google Cloud Platform (GCP), REST, Django, Machine Learning, Docker, PostgreSQL, JavaScript, Python, Architecture, CTO, React Native, Python 3, Object-oriented Programming (OOP), Containerization, REST APIs, Full-stack, APIs, AWS Lambda, Amazon Web Services (AWS), Front-end, Data Cleaning, Mypy, Algorithms, JSON, Agile, Stripe API, Angular, PyCharm, NGINX, Data Scraping, Web Development, Django ORM, CSS, Django REST Framework

Python Developer

2018 - 2019
For Days, Inc
  • Helped to move the eCommerce platform from legacy codebase to the modern frameworks and libraries such as Django and React.
  • Proposed to stakeholders an off-the-shelf, Python-based solution for managing all back office activities. This way, we've met a deadline to launch a new platform version.
  • Helped with a transition from a subscription-based business model to a one-time purchase business model collaborating with the team.
Technologies: Python, Flask, React, Django, Stripe API, Git, JavaScript, GitHub, PyCharm, NGINX, Django ORM, CSS, Django REST Framework

CTO, Back-end Developer

2013 - 2015
Diabetes Lab
  • Developed both back end and front end and maintained a web application for people with Type 1 diabetes that eases managing their disease; also integrated various data sources, such as devices, APIs, and so on.
  • Created an application that was responsible for aggregating data from various fitness trackers, such as Jawbone and Fitbit, and based on the wavelet theory, I was able to detect some health-related patterns.
  • Conducted over 100 interviews with customers to understand what are patients' real-life problems based on which team could decide on the next thing to implement.
  • Delivered four MVPs, including one mobile application and a web platform. In addition to that, I was responsible for the creation of the R&D plan, connecting with various stakeholders, and scouting talents.
Technologies: Management, Scrum, Agile, Docker, PostgreSQL, SQLAlchemy, Flask, Django, Machine Learning, JavaScript, Python, Architecture, Object-oriented Programming (OOP), Full-stack, REST APIs, Jira, HTML5, Algorithms, Facebook API, Git, PyCharm, NGINX, Django ORM, CSS, Django REST Framework


2012 - 2015
Nicolaus Copernicus University
  • Coordinated a scientific grant that was awarded by the National Science Center.
  • Created an algorithm for computing so-called tilted modules in certain algebraic structures.
  • Conducted classes with students, particularly basics of algebra, logic, and first-order logic, which is the basis of SQL.
  • Taught the Prolog programming language to students.
  • Reviewed scientific papers to ensure publishers' criteria are met.
Technologies: LaTeX, TeX, Mathematics, PostgreSQL, PHP, Prolog, SQL, MySQL, Maple, Python, Algorithms

Sports Betting Tool

A Python-based app for automating sports bets.

A client wanted to create a product that would help him automate the process of placing bets on multiple bookmakers' sites.

• Translating business needs into technical designs.
• Handling day-to-day coding activities that included architecture design, writing tests and code, and integration with external services.
• Managing technical debt.

• Created over 30 bots that could perform multiple actions.
• Automated over five business processes of different complexities.
• Introduced good coding standards.

Tax Settlement App

A Python and Angular-based app that was designed to ease tax settlements for people working in Germany. Together with the team, we created a product that was used to push over 10000 tax statements to a tax office in the first year.
One of the things we were the proudest of was suggesting to the client a web-based person authentication tool - Onfido that, taking into account business context and law in Germany, was a novel idea allowing further automation of the whole process.

Education Platform for Entrepreneurs

A Python and Javascript-based education platform.

A client was building a product that was a content-rich education platform for entrepreneurs living in rising markets, such as Vietnam and Cambodia. The client wanted to put a strong focus on high-quality video-based content.

• Handling day-to-day coding activities that included architecture design, writing tests and code, and integration with the front-end application.
• Managing technical debt.
• Gathering business requirements from all stakeholders.

AI Student Advisor

A GPT-based module for recommending the best course for a student based on the student's preferences and education history. In the project, the flow of a conversation with the student was designed to retrieve all information that might be suitable for determining a course that the student might be interested in.
2008 - 2012

PhD in Mathematics

Nicolaus Copernicus University - Toruń, Poland


Django ORM, REST APIs, Stripe API, PayU API, SQLAlchemy, Flask-RESTful, Amazon Rekognition, jQuery, Jira REST API, Facebook API, React, Twilio API, Requests, PayPal API, SendGrid API, TensorFlow, Telegram Messenger API, Mypy, Stripe


RabbitMQ, LaTeX, NGINX, Jira, Bitbucket, Docker Compose, PyCharm, Maple, Confluence, Celery, Git, cURL Command Line Tool, Apache, GitHub, Ngrok, CircleCI, GitLab CI/CD, Mailchimp, ShipStation, AutoML, Pytest


Django REST Framework, Flask, Django, Selenium, Bootstrap, Angular, React Native


Python, Python 3, TeX, HTML5, CSS, SQL, Prolog, PHP, CSS3, JavaScript, TypeScript, Rust


Amazon S3 (AWS S3), PostgreSQL, JSON, MySQL, Redis, SQLite, Docker Cloud, Google Cloud


Agile, REST, Continuous Integration (CI), Management, Scrum, Unit Testing, Continuous Delivery (CD), Test-driven Development (TDD), Agile Software Development, Object-oriented Programming (OOP)


Docker, Google Cloud Platform (GCP), Amazon EC2, Amazon Web Services (AWS), Debian, OS X, AWS Lambda, Blockchain


Mathematics, Architecture, Machine Learning, Software Architecture, Customer Discovery, CTO, APIs, Containerization, Algorithms, Web Scraping, Data Scraping, Web Development, Code Architecture, MLflow, Business Analysis, HAProxy, DNS, Gunicorn, Tesseract, API Integration, Multiprocessing, Full-stack, Front-end, Data Cleaning, OpenAI GPT-4 API, OpenAI, Retrieval-augmented Generation (RAG)

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