Projects & Portfolio

High-Performance, Cache-Local Hash Map in RustGoal: Creating a specialized hash map for performance-critical systems (LLM tokenizers, databases) that outperforms standard implementations by maximizing CPU cache utilization.

Precise OS is a custom-built automation platform designed for efficient LinkedIn data extraction and contact lead management. It enables users to systematically collect profiles, job titles, and company data while minimizing manual effort and maintaining compliance with LinkedIn’s platform constraints. This project demonstrates expertise in web automation, data engineering, and system reliability under real-world constraints.

Vault‑Track is an open‑source inventory and access tracking system designed to help teams securely monitor and manage stored items, access events, and usage history. The application provides a structured way to register assets (equipment, tools, valuables), track who accessed them and when, and maintain a reliable history of check‑ins/check‑outs. It aims to improve accountability, reduce loss, and streamline physical asset workflows. This project highlights skills in full‑stack development, secure state tracking, and user‑centric application design. https://www.vaulttrack.org/

Lexi Drift is an AI‑assisted language learning platform designed to help users memorize vocabulary efficiently using multi‑sensory methods and adaptive repetition. The system combines spaced‑repetition scheduling (FSRS) with visual, auditory, and contextual learning to enhance long‑term retention and make learning possible anytime — even passively during daily activities like commuting or exercising. Technical challenges tackled: https://lexidrift.com/

I was responsible for tech leading of team implementing backoffice processes connected with verification and collection of sport data, I mapped data flow and connections between systems and described it in documents, that improved cross teams communication in company. Huge challenge was also decoupling backend from database shared with another team. It was achieved by imposing introduction of Open API and building strongly typed contract between database and services. I removed all data models written by hands but following schema defined by other team and replaced them by introspection from database. Finally I replaced web-socket communication between backends by queue increasing stability and scalability from 1k events per second to 12k events per seconds.

My responsibility was auditing project with 7 years history and 1M lines of code. Goal of audit was analysis of mistakes that led to overspend budget, grade current state of code base and advise how to develop MVP from current code. Additionally I setup CI/CD and IaC for project and hired new team for this project. laravel, vue, gitlab, mysql, python, postgresql, docker

Communication hub for real estate managers. In this project I was one of 15 developers working together. We created e-mails, sms and calls integration allowing to manage all communication in single app. express, mongo, redis, elastic search, typescript, nest js, graphql, vue

I was not creator of this project, but maintainer. I rewrote 87% codebase to typescript, documented db models and views, optimized some crucial views in admin panel and detected some critical security bugs, that I fixed. meteor, mongo, react

A micro service for extracting names, surnames, e-mail addresses and telephone numbers from CV files. At the moment it is 97% effective, but is still being expanded and improved. The first version was 70% effective. The task of the system is to support the automation of recruitment processes. It is used in Interview Record. At the moment, he has processed nearly 500 CV files. I plan to add another 20 hours, increase the efficiency to 99% and sell this tool in the saas model. V1: python, flask, sqlalchemy, graphql V2: node js, fastify, rest, prisma js, vue, tailwind

A platform that detects signals in the cryptocurrency market and sends them to groups on a telegram. The system uses the architecture of microservices which are data producers or recipients. Kafka is used for communication between them. Data analysis needed to verify that the signals worked in the past were performed in Mongo Charts, Mathematica, Python and Node JS. The system is actively used by several dozen people who pay a subscription and finance new functionalities. The system detected 20% earning events, 8% tweets and 40% margin changes. Currently, a landing and smart contract are being created to help increase the number of users and promote the system. The biggest challenge in the project is still the investment risk assessment. To this end, in July, the team was joined by a Doctor of Mathematics from the University of Oxford, who professionally deals with transaction machines. V1 python, mongo atlas V2 node js, typescript, mathematica

A website where the holders of Swiss franc loans can find out which law firms are best at dealing with matters similar to their case. The selection of the law firm is based on the exploration and exploitation algorithm exp3 on the basis of the history of nearly 5,000 judgments in cases handled by 80 law firms. The service has already been used by 150 users whose phone numbers have been confirmed by SMS verification. Currently, the client is investing in SEO and attracting traffic to the website. The business model is based on fees payable to the Law Firm for generating leads. V1 wordpress, strapi, fastify, typescript, prisma, mysql

A platform that allows you to manage access to video training for the financial industry. Videos are uploaded to digital ocean space, metadata is set in CMS webflow, access and user management is done in the strapi panel. User views are written in nuxt. There are nearly 150 films on the platform with a total volume of over 300 GB, divided into 8 training courses. Almost 200 users have used it. It should be noted that these are trainings costing from several hundred to several thousand zlotys and after incurring the cost of implementation, the client could resign from the saas platform, which costs him 4,000 zlotys / month. V1 strapi, vue, webflow, digital ocean space, mysql

A calculator calculating the potential financial benefits that may be obtained by a franchise holder with various variants of the revision of his Swiss franc contract. Banks used illegal provisions in their contracts for Swiss franc loans, and now the holders of such loans can solve their problems in various ways. The calculator is written in nuxt and is based on python API for calculations and node js for sending e-mails. The aim of the project was, above all, to create the best-looking calculator and, at the same time, generate leads for Swiss francs at the lowest possible cost. The system regularly brings in several leads per month. It should be noted that the potential conversion of such a lead means for the law firm a loan for several hundred thousand zlotys, of which several dozen are usually recovered. V1 nuxt, python, node js

System for e-mail dispatch that allows you to select a group of recipients, change their names in salutation phrases, attach attachments and set permanent elements, such as footer and header. The system has integration with emaillabs and sendgrid, it independently divides large mailings into fragments released within the queue. I don't know how many e-mails were sent from this system, but I estimate it is tens of thousands. The system is actively used by users who send personalized e-mails with information about the current offer. V2 - nuxt, fauna, node js, fastify, ejs, unzipper https://mailing.preciselab.space/readme

Maintenance and development of an application that supports remote health coaching for corporate employees. The scope of work included expanding the system with group chats, simplifying boarding, refactoring the mobile application code, expanding the chats with video, audio and image attachments. I wrote a backend in node js that covered the old backend in rails with a graphql layer. A group web chat was written. The vast majority of the components were rewritten in the mobile application. Standard maintenance works were carried out. The microservices were created, for example, for caching queries to vimeo and converting m4a and caf files to mp3. rails, apollo server, fastify, expo

Szkoła Umysłu SOWA is an online learning platform focused on mental arithmetic and rapid calculation skills development. The system delivers structured training in techniques like abacus-based mental math (e.g., Soroban) and fast calculation through guided exercises and group lessons for children, youth, and adults. It includes a student portal where learners can log in, complete assignments, and access personalized practice, as well as administrative features for instructors.

InterviewRecord is a web-based recruitment platform that enables companies to conduct asynchronous video interviews at scale. The system allows recruiters to create custom interview flows, define question sets, invite candidates to record video responses, and review submissions collaboratively. It streamlines early-stage screening, reduces scheduling overhead, and improves candidate evaluation beyond traditional CV-based filtering. Vue, Mongo, Typescript, Jest, s3, rust, python

A website that allows you to book accommodation in interesting places close to nature in Poland. Equipped with a search engine and advanced filtering, a blog with a comment system. The mechanism of evaluating and commenting places, including the confirmation of stay. Booking system with built-in chat. The logic of the website was prepared and tested, but after testing on users, it was decided that the visual layer should be replaced in the website. Subsequently, the project was put on hold by a pandemic. Currently waiting for a new design. V1 nuxt, strapi, tailwind, docker

Internet monitoring system. Composed of microservices, console tools and a browser plug. Focused around the mongo base on the atlas with mongo realm functions. The system supports the collection of data about users and posted content from the websites: Facebook, Instagram, Twitter, Gowork and LinkedIn. Gets statistics from Google Trends and Social Blade. Enriches the data with the analysis of the sentiment of statements. It integrates with Sentione and Brand24 systems. The system allowed for the collection of hundreds of thousands of mentions from the Internet. While writing it, a package was created https://www.npmjs.com/package/fb-date-parser. Thanks to the collected data, the client can verify the hypotheses regarding social media. fastify, nuxt, mongo charts, mongo realm, chrome extension, node, typescript, kafka, terraform

Platform that allows you to conduct coaching for clients of psychologists. Main features was chat, exercises for clients, and editor of psychological tests. In this project I learned how to write mobile apps in expo. expo, node js, php, symfony, vue

The website allows you to create tickets and operate on user balances through transfers or direct updates. Any changes to the balance are saved in the system. Tickets are modeled by state machines. node js, prisma, vue, graphql

A website enabling the provision of medical data to doctors. The patient can describe ailments, add medications, insert individual photos, galleries, notes.

I have developed and implemented a dynamic valuation algorithm. It allows you to examine the demand curve and coincide with the optimal price in the minimum number of steps. https://precise.sale and https://medium.com/@precisesale. The first version of this system was written in PHP. I learned a lot about API design while creating this system.

Website for purchasing computing power for mining cryptocurrencies. It allows you to purchase predefined contracts or select the amount of computing power. node js, meteor, vue

The application allows you to search and add training announcements. The most interesting feature of the system is the very fast search engine. node js, vue

A system for a company that operates specialized servers. His tasks include intercepting customer correspondence, analyzing it, creating reports and calling employees. But at the heart of the system is a failure risk assessment engine that helps optimize purchasing decisions and part placement. node js, meteor, vue

I created a speedway competition management system for the Polish Motor Association. The system allowed managing the teams and their composition, generating games, assigning players to them, saving the results, viewing statistics, and saving reports on the condition of the tracks. Several dozen tables and views, users with different levels of permissions, a lot of checks related to sports rules, such as a certain number of competitors of a given age assigned to the competition, or, for example, the rules of choosing who rides with whom in which race. Full audit log. The implementation of this solution saved a huge amount of work, previously done manually. One central system was created that enabled analysis of the results and generating reports in an automated manner. Nobody had to manually write down the order of races, check the correctness of the team line-up, and track checks by the judges were available online for the organizers of the competition. symfony, mysql, cypress

A service that allows students to be assigned to courses, giving them access to teaching materials in the form of interactive HTML presentations or files. The system supports the process of reporting errors in presentations and advanced logic of updating materials during various courses. The complete history is followed. symfony, twig

The program ran on 20 VPS, each with 300 GB. I downloaded and processed the data in one day. I increased performance by using parallelization and a custom compressor written in python and C ++.

Correlations between stock exchange instruments were calculated. The program enables the visualization of the evolution of the correlation network in 3D.

User management and system administration functions that scan, connect and link different product databases to a highly optimized search engine.

I collected stock data and wrote trading bots. Using machine learning and other math tools, I tried to write a trading algorithm. No success, but the experience gathered was worth it.

In this project I researched for multivariate integrals in the base of Gaussian functions. Much work was done on equation operations, but in the end numerical computation was used. https://preciselab.fra1.digitaloceanspaces.com/blog/pr3-v3.pdf

Written in Pascal, the program used fuzzy logic methods to recognize the language of a text using a minimum number of characters. It was written because I was fascinated by the topic. Not posted on the Internet. 2010 - Further C ++ learning. Learning about Mathematica, Fortran, Pascal, Perl, Python, LaTeX. 2007 - The first console text game in C ++ 2006 - I installed the first Linux. I started learning C ++ and assembler.