Szymon is available for hire
Hire SzymonSzymon Stasik
Verified Expert in Engineering
JavaScript Developer
Warsaw, Poland
Toptal member since November 30, 2020
Bio
Szymon is a proactive software engineer, architect, and problem solver with 20 years of experience. He has led successful projects in complex multi-tier large-scale systems and early-stage startups. Szymon's experience can be seen in many on-site and remote worldwide projects for the public sector, insurance, finances, travel, advertising, entertainment, and mobile.
Portfolio
Eukid.io
Node.js, NestJS, Prisma, PostgreSQL, Ionic, Angular, Capacitor, iOS, Android...
Accountable2You LLC
Angular, Ionic, Capacitor, Cypress, Sass...
Agentic AI Real Estate Management Platform
Artificial Intelligence (AI), ChatGPT API, ChatGPT Prompts, AI Agents...
Experience
- JavaScript - 20 years
- Java - 18 years
- Node.js - 11 years
- Angular - 11 years
- TypeScript - 8 years
- Docker - 6 years
- Ionic - 6 years
- Artificial Intelligence (AI) - 3 years
Work Experience
Tech Founder
2024 - PRESENT
Eukid.io
- Architected a multi-modal agentic pipeline to autonomously generate synchronized audio, images, and content via ElevenLab for comic books asset app assembly.
- Created an edutech platform helping children learn to read. It features word-by-word synchronized audio, AI narration, and gamification, built on a modern Angular/NestJS stack. It addresses a specific market need with scalable, high-quality content.
- Integrated FFmpeg for automated asset assembly and established the foundational pipeline for scalable video avatar generation. This component enables the synthesis of dynamic, character-driven educational video content from generated assets.
Technologies: Node.js, NestJS, Prisma, PostgreSQL, Ionic, Angular, Capacitor, iOS, Android, Mobile, Generative Artificial Intelligence (GenAI), Whisper, Video Codecs, Tortoise TTS, Text-to-Speech (TTS), Speech-to-Text (STT), Speech Recognition, ElevenLabs Solutions, Video & Audio Processing, Video Processing
Mobile Developer
2024 - 2025
Accountable2You LLC
- Delivered a complete MVP transformation of an incomplete project into a production-ready mobile app, featuring notification capabilities, advanced filtering, native platform integration, and modern architecture, including migration from Apache Cordova to Ionic Capacitor v6.
- Established a complete CI/CD Fastlane pipeline for automated iOS and Android builds, and comprehensive testing infrastructure, automated build numbering, version management, local notification testing capabilities, and App Store deployment workflows.
- Modernized Angular architecture by migrating to Angular Query for state management, implementing signals-based reactivity, and upgrading the framework from the legacy version to Angular 17.1 with modern control flow.
- Architected and implemented a comprehensive push notification system, background processing, custom native Capacitor plugins for badge count, silent notifications, real-time count sync, and cold-start processing across iOS and Android platforms.
- Standardized UI/UX components with a comprehensive design system, including color palette extraction, asset organization, advanced filtering capabilities, and consistent styling patterns using SASS/SCSS with Angular signals-based state management.
- Built robust offline handling and network connectivity management, ensuring application functionality during network interruptions.
Technologies: Angular, Ionic, Capacitor, Cypress, Sass, Amazon Simple Notification Service (SNS), Apple Push Notifications, Firebase, Jasmine, CSS, SCSS, Kotlin, Swift, Android, iOS, Mobile Apps, App UX, Mobile UX, CI/CD Pipelines, Xcode, Git
Lead Full-stack & AI Engineer
2024 - 2025
Agentic AI Real Estate Management Platform
- Architected and developed a comprehensive agentic AI real estate management platform MVP from concept to production, serving homeowners, residents, HOAs, and commercial properties with intelligent automation capabilities.
- Built sophisticated AI agents for automated document processing that intelligently extract and analyze property-related documents, including leases, maintenance records, and legal documents, reducing manual processing time by 90%.
- Conducted comprehensive evaluation of cutting-edge agentic AI development tools: Cursor, Windsurf, GitHub Copilot, Cline, establishing best practices for AI-assisted dev workflows and guiding team adoption with responsible implementation strategies.
- Introduced AI-assisted development methodologies, pair-programming approaches with AI tools, comprehensive code review workflows, and memory bank systems to maintain codebase awareness across agentic coding sessions, improving development velocity.
- Implemented Perplexity integration to enhance AI response quality for resident inquiries, achieving contextually accurate responses and significantly improving user satisfaction metrics.
- Developed comprehensive CI/CD pipelines and DevOps practices, including automated testing, deployment automation, and monitoring systems, ensuring 99.9% uptime and reducing deployment time from hours to minutes.
Technologies: Artificial Intelligence (AI), ChatGPT API, ChatGPT Prompts, AI Agents, Agentic AI, Agentic Frameworks, LangGraph, Embedding Models, Large Language Models (LLMs), NestJS, Google Cloud Platform (GCP), Docker, PostgreSQL, Pgvector, Supabase, Python, FastAPI, Tailwind UI, Tailwind CSS, AI Chatbots, AI Consulting, AI-generated Code, AI-enabled Applications, AI-augmented Software Engineering (AIASE), AI-enabled Search, Claude, Claude API, Cursor AI, Windsurf, OpenAI, OpenAI API, Serverless GPUs, AI Integration, Back-end Development, Distributed Systems, Real-time Data, NumPy, Scikit-learn, Anthropic, Prompt Engineering, Retrieval-augmented Generation (RAG), Workflow, Workflow Automation, Workflow Automation & System Integration, Git, Generative Artificial Intelligence (GenAI)
Capacitor Expert (via Toptal)
2023 - 2024
99math
- Transformed 99math's Vue web app into a fully functional cross-platform mobile app using Capacitor. Successfully published to the App Store and Google Play Store. The published app generated immediate organic installations and subscription growth.
- Implemented dedicated in-app payments using RevenueCat for digital subscriptions and consumables, integrating cross-platform eligibility and Stripe for payment processing. This resulted in a steady increase in active subscribers and in-app purchases.
- Developed comprehensive automation pipelines with CircleCI and Fastlane. Improved builds and deployment processes along with Appium tests. It greatly enhanced development efficiency and reduced errors while supporting the existing development process.
- Established a continuous deployment strategy using dedicated code-push, aligning with the existing team's workflows and ensuring seamless updates without frequent app store submissions.
Technologies: Ionic, Android, iOS, Capacitor, Vue, Fastlane, CircleCI, RevenueCat, Stripe, Push Notifications, Apple Push Notifications, OAuth, Appium, Mobile UX, Xcode, AI Integration, Git, Audio Processing, Prompt Engineering, Generative Artificial Intelligence (GenAI)
Lead Full-stack AWS/Node.js Engineer
2023 - 2023
Creator Source
- Took over the initial proof of concept (POC) and led the implementation and production launch of an MVP of an educational platform for social media creators.
- Introduced CI/CD practices, credential vault, deployment pipelines, and end-to-end integration testing to recover from early POC tech debt.
- Designed the back-end architecture and migrated a POC draft AWS Lambda code into a well-structured modularized and tested serverless NestJS codebase.
- Configured the dockerized environment for local development and GitHub Actions pipelines integrating AWS Lambda stack and WordPress instance.
- Designed and developed a proof of concept for an AI-assisted gamification engine, aiding users in selecting actions from the curriculum and providing a chat feature for discussing specific details.
- Migrated legacy WordPress features to a mobile app with code reuse to coexist with WordPress as a modern, single application matching all styles and components, leveraging the Ionic/Capacitor framework and the components library.
Technologies: JavaScript, TypeScript, AWS Lambda, NestJS, MongoDB, Continuous Delivery (CD), Artificial Intelligence (AI), Gamification, WordPress, Docker, GitHub, Monorepos, JavaScript Testing, Database Migration, Mobile First, Search Engine Optimization (SEO), Angular Universal, System Administration, Amazon Simple Queue Service (SQS), Facebook API, Vault, Push Notifications, Apple Push Notifications, Web Security, Web App Design, Selenium, NPM, RESTful Web Services, Software Design, Full-stack Development, Natural Language Processing (NLP), API Gateways, Chatbots, Ionic, Angular, JSON Web Tokens (JWT), Node.js, LocalStack, AWS NAT Gateway, Amazon CloudFront CDN, Technical Architecture, Testing, Payment APIs, Data Processing, UX Design, OpenAI, Mobile UX, Java Servlets, Back-end Development, Git, WebStorm
Lead Full-stack Node.js/Angular Engineer
2022 - 2023
Apprentice
- Built a drug recipe publishing back-end framework that shares recipes between sites and labs. Enabled multiple API instances to communicate with each other.
- Built the MVP for the enterprise business. This work included enabling features that helped engage tenant integrations, share information between teams, and manage teamwork.
- Extended a local Docker environment to support multiple API instances running locally and replicating production configuration.
- Introduced Dockerized environment to GitHub Actions CI/CD E2E integration testing pipelines, solved intermittent test flakiness, and improved test execution by 40%.
- Refactored a legacy lifecycle/versioning scheme of a key business entity in the system.
- Implemented a soft delete feature for a MongoDB driver level across many entity types.
Technologies: Angular, Express.js, TypeScript, Docker, Continuous Integration (CI), MongoDB, Mongoose, Cypress, Amazon Web Services (AWS), NestJS, NgRx, Apollo, AG Grid, i18n, Spreadsheets, GitHub, GitHub Actions, Monorepos, JavaScript Testing, Redis Cache, Selenium, NPM, RESTful Web Services, Swagger, Full-stack Development, Customer Relationship Management (CRM), Testing, Data Processing, Back-end Development, Distributed Systems, Git, WebStorm
Senior Full-stack Node.js/AWS/Angular Engineer
2022 - 2022
Verb Technology Inc.
- Built a video conference stream management layer that enables adding new video presentation features.
- Created a local Docker-based/LocalStack environment to drastically speed up development and support testability and debugging, enabling developers to run all required back-end and front-end components locally.
- Refactored and decoupled legacy authentication and token management code on the back end and front end, introducing good practices and ensuring testability.
- Introduced integration testing practices to the project and helped make others comfortable with integration testing.
Technologies: Angular, Node.js, TypeScript, NoSQL, Express.js, Amazon Web Services (AWS), Docker, Monorepos, JavaScript Testing, Redis Cache, Web App Design, NPM, RESTful Web Services, Swagger, Full-stack Development, Chai, AWS NAT Gateway, Testing, TCP/IP, Back-end Development, Real-time Data, Git, Audio Processing
Lead Node.js/AWS Developer, DevOps Coach
2021 - 2022
Toptal Client
- Developed a framework that manages tasks of accessing an external API and web scrapers. After introducing the framework to the team, they used it to control dozens of web scrapers and simple API clients.
- Coached the CEO and business team on the DevSecOps transition, allowing the development, security, and operations teams to work closely together.
- Handled the DevSecOps transition by shortening release cycles, strengthening feedback loops, introducing a fully-featured incident management system, and including risk and security management in the development cycles.
- Mentored the development team on coding practices, code reviews, CI/CD pipelines, and testing of the serverless codebase.
- Wrote a proof of concept for an electron desktop app for business people to integrate with a new partner API, i.e., to access their product catalog. and prices and perform basic analytics.
Technologies: TypeScript, Node.js, Amazon Web Services (AWS), JavaScript, DevOps, AWS DevOps, DevSecOps, Amazon DynamoDB, Amazon S3 (AWS S3), Serverless Framework, Serverless Architecture, Web Scraping, Docker, Jest, Yarn, Yarn Workspaces, AWS Lambda, Agile Coaching, APIs, CI/CD Pipelines, Continuous Delivery (CD), Amazon EC2, QA Testing, QA Automation, Amazon ElastiCache, Fintech, Software Architecture, Headless Software, Third-party APIs, Scalability, Amazon RDS, Lambda Architecture, Electron, Monorepos, JavaScript Testing, Amazon Simple Queue Service (SQS), Amazon Simple Notification Service (SNS), Apple Push Notifications, Visual Studio Code (VS Code), Puppeteer, Web Security, Web App Design, Web Design, AWS AppSync, DYNAMO, Event-driven Architecture, Beautiful Soup, Scrapy, Selenium, NPM, RESTful Web Services, Data Scraping, Software Design, Swagger, Full-stack Development, API Gateways, LocalStack, AWS NAT Gateway, Amazon CloudFront CDN, Scraping, Technical Architecture, Vercel, Cryptography, Payment APIs, Data Processing, UI Design, Back-end Development, Distributed Systems, Real-time Data, Go, Git, Crypto, Blockchain
Founding Mobile Developer (iOS/Android)
2018 - 2022
MeeTheLocal
- Developed and published an Ionic and Angular-based marketplace mobile app to the App Store and Google Play Store. The app matches long-term international travelers with residents to help solve problems abroad.
- Created a DevOps staging environment with CI/CD pipelines, the mobile app builds, Appium E2E tests in the cloud for Android and iOS, private npm repository, logs system, and user metrics analytics.
- Developed mobile marketplace API back end using MongoDB and GraphQL.
- Designed and introduced a beta testing iOS and Android provisioning system based on Fastlane, Fabric, and Crashlytics (now Firebase Crashlytics).
- Integrated the Hashicorp vault to keep secret keys and credentials off the source repositories.
Technologies: Cross-platform App Development, HTTP, App Store, Google Play Store, Startups, Mobile App Development, Cross-platform, Geolocation, Figma, TypeScript 3, Firebase Realtime Database, Firebase Authentication, Agile, Serverless Architecture, Serverless, Mobile Architecture, Responsive Web Design (RWD), Early-stage Startups, User Interface (UI), User Experience (UX), APIs, Web Architecture, Maps, Google Maps, Google Maps API, SaaS, GitHub, Bitbucket, Minimum Viable Product (MVP), Backendless, HTML5, CSS3, REST APIs, Technical Leadership, HTML, Cloud, Full-stack, Front-end Development, Front-end, Single-page Applications (SPAs), Progressive Web Applications (PWAs), Crashlytics, Architecture, DevOps, Microfrontends, Firebase, ECMAScript (ES6), Integration Testing, Object-oriented Programming (OOP), JSON, Internationalization, Mailgun, Lean Startups, Web App Development, Web Development, NoSQL, i18n, New Relic, WebSockets, CSS, Sass, Sinon.JS, Mocha, NGINX, Vault, UXCam, Passport.js, Intercom, Facebook API, NgRx, Web Components, Capacitor, jQuery, Groovy, Terraform, PWA, MongoDB, OpenVPN, Google Cloud Platform (GCP), Express.js, User Metrics, E2E Testing, A/B Testing, Firebase Android SDK, Google Analytics, Mobile Analytics, Analytics, Mobile, Google Cloud, Linux, MacOS, iOS, Gradle, Android, Apple Push Notifications, Push Notifications, Karma, TypeORM, NestJS, Cypress, Protractor, Jasmine, Appium, Continuous Integration (CI), Continuous Delivery (CD), Kanban, Jira, Private NPM Modules, CircleCI, KVM, Docker, Graylog, RxJS, Android SDK, iOS API, Intercom API, OneSignal, Bugsnag, Firebase Analytics, Google Login, X (formerly Twitter) API, Apple, Facebook Login, OAuth 2, OAuth, Fabric, Fastlane, Apollo, GraphQL, REST, Parse Server, Webpack, Node.js, Ionic 4, Ionic 3, Angular, Ionic, TypeScript, JavaScript, Mobile Development, Unit Testing, Requirements Analysis, MEAN Stack, Reactive Programming, Security, CTO, GitFlow, Mobile Apps, Cordova Plugins, Cordova, Xcode, Swift, CI/CD Pipelines, Prisma, QA Testing, QA Automation, Web Applications, Web & Mobile Applications, Web Application Architecture, SCSS, Software Architecture, Headless Software, Travel, PWABuilder, JavaScript Testing, Mobile First, Search Engine Optimization (SEO), Angular Universal, System Administration, Firebase Cloud Messaging (FCM), Google Cloud Functions, Flutter, Web Security, Web App Design, Web Design, Selenium, NPM, Software Design, Postman, Full-stack Development, RDBMS, Technical Architecture, Testing, Payment APIs, Mobile UX, Back-end Development, Git, Audio Processing
Lead Mobile Developer (iOS/Android/Node.js/AWS), Architect
2021 - 2021
Toptal Clients
- Developed an Ionic and Angular mobile app for equine and canine therapists.
- Created a mobile app build pipeline including releases to test users via Firebase distribution (former Crashytics).
- Designed and implemented GraphQL API to support better synchronization between the business and developers and between front-end and back-end developers.
Technologies: Angular, Ionic, Capacitor, GraphQL, Node.js, AWS Lambda, Serverless Framework, Mobile Apps, Firebase, Stripe, PostgreSQL, Amazon Cognito, Xcode, Twilio, Twilio API, Firebase iOS SDK, Firebase Android SDK, Firebase Analytics, Agile, DevOps, CI/CD Pipelines, QA Testing, QA Automation, Web Applications, Web & Mobile Applications, Web Application Architecture, User Interface (UI), SCSS, Software Architecture, Third-party APIs, Mobile App Development, Mobile Development, Lambda Architecture, MySQL Server, PWABuilder, JavaScript Testing, Mobile First, Angular Universal, System Administration, Push Notifications, Visual Studio Code (VS Code), Flutter, Web Security, Web App Design, AWS AppSync, NPM, RESTful Web Services, Software Design, Postman, Swagger, Full-stack Development, Chai, API Gateways, AWS NAT Gateway, Amazon CloudFront CDN, Technical Architecture, Testing, Payment APIs, Mobile UX, Back-end Development, Git
Full-stack Engineer (Angular/Node.js/Firebase)
2020 - 2021
CRS Ventures, LLC
- Implemented an Angular-based user management and authorization module.
- Reworked Angular application state management to resolve state-related issues.
- Introduced an E2E testing suite to ensure release reliability.
Technologies: Angular, JavaScript, Firebase, TypeScript, Jest, Akita, Application State Management, AngularFire, Cloud Firestore, Material UI, Angular Material, GitFlow, Lambda Functions, CI/CD Pipelines, Charts, Scalability, Apple Numbers, Microsoft Excel, Spreadsheets, Google Cloud Platform (GCP), Google Cloud Functions, NPM, RESTful Web Services, Full-stack Development, API Gateways, Testing, Data Processing, Google BigQuery, Back-end Development, Accounting, Finance, Git
Lead Full-stack Engineer (Java/Node.js/React/GraphQL/Mobile)
2016 - 2020
Vrbo (via Luxoft Mexico)
- Designed and led the development of a GraphQL API for a cross-brand property status service utilized by over 40 million unique users.
- Refactored a legacy JSP rental property owners' management platform to React and GraphQL self-contained components (micro-frontends). The average loading time improved by 60%, and user engagement enhanced by over 25%.
- Supported the growth of a contracting team in Mexico from zero to 50+ people in 3.5 years. This included interviewing new members, participating in quarterly business reviews with CXO level from the customer, and working in the strategic growth team.
- Introduced and advocated the adoption of TypeScript in the first company-wide project. Based on that, TypeScript was widely adopted across company projects.
- Migrated the property owner acquisition legacy application to a microservices continuous delivery architecture and integrated with internal A/B testing tools.
- Proposed key improvement changes and applied them to a new solution for the rental property lifecycle engine.
- Introduced new features into a React Native mobile app, Vrbo Owner, for vacation rental property owners, including Appium testing, A/B feature flags, and i18n. This app is available at the App Store.
Technologies: HTTP, Apache Kafka, API Integration, Startups, Kubernetes, Apollo Server, Continuous Development (CD), Leadership, React Redux, TypeScript 3, Agile Coaching, Agile, Redux, Responsive Web Design (RWD), User Interface (UI), User Experience (UX), XML Web Services, APIs, Web Architecture, Microservices Architecture, GitHub, Minimum Viable Product (MVP), Model View Presenter (MVP), HTML5, CSS3, Redis, REST APIs, Technical Leadership, HTML, Cloud, Back-end, Full-stack, Front-end Development, Front-end, Single-page Applications (SPAs), Amazon Web Services (AWS), Mobile, Mobile Analytics, Appium, REST, Jest, Progressive Web Applications (PWAs), PWA, Microfrontends, Pair Programming, Production Support, Technical Support, ECMAScript (ES6), Integration Testing, Object-oriented Programming (OOP), JSON, SAML, Internationalization, Key Performance Metrics, User Metrics, E2E Testing, A/B Testing, Kanban, Scrum, Objectives & Key Results (OKRs), Continuous Deployment, Continuous Delivery (CD), Continuous Integration (CI), Web App Development, Web Development, NoSQL, SQL, Redis Cache, i18n, Haystack, Ansible, OAuth, Kibana, Telegraf, Elasticsearch, Splunk, PagerDuty, Datadog, New Relic, iOS API, WebSockets, CSS, Mocha, NGINX, Android SDK, Android, Apollo, Protractor, Jasmine, RxJS, Web Components, Karma, Mockito, JUnit, jQuery, Jenkins, Groovy, Terraform, Kotlin, JSON Web Tokens (JWT), Microservices, MongoDB, Java, Docker, Linux, React Native, InfluxDB, Grafana, Spring Boot, Dropwizard, Kafka Streams, RabbitMQ, TypeScript, JavaScript, GraphQL, Hapi.js, Webpack, React, Node.js, MySQL, Spring, Hibernate, Jakarta Server Pages (JSP), Apache Maven, Java EE 8, Requirements Analysis, Reactive Programming, Security, Team Leadership, GitFlow, CI/CD Pipelines, QA Testing, QA Automation, Web Applications, Web & Mobile Applications, Web Application Architecture, SCSS, Charts, Data Visualization, Software Architecture, Headless Software, Travel, Third-party APIs, Scalability, Flutter, Amazon RDS, Next.js, Monorepos, JavaScript Testing, Database Migration, Mobile First, Incident Management, Vault, Site Reliability Engineering (SRE), Azure, Puppeteer, Web Security, Web App Design, Web Design, Event-driven Architecture, Selenium, NPM, RESTful Web Services, Software Design, Swagger, Full-stack Development, Customer Relationship Management (CRM), Chai, Office Add-ins, RDBMS, API Gateways, Chatbots, Swift, Okta, Technical Architecture, JetBrains IDE, Testing, Cryptography, TCP/IP, Data Processing, UX Design, UI Design, Microsoft SQL Server, Java Servlets, AI Integration, Back-end Development, Distributed Systems, Real-time Data, Git
Lead Full-stack Node.js/iOS/Android Mobile Engineer
2015 - 2016
Navionics SPA (via Luxoft Poland)
- Led the development of a marine navigation web application used by 100,000 users worldwide.
- Developed the Ionic POC of a hybrid mobile marine navigation mobile app, Navionics Boating, to reuse web navigation UI and logic between web and mobile. This app is available at the App Store.
- Designed and developed continuous integration pipelines for a web application.
Technologies: OpenStreetMap, Mobile App Development, Cross-platform, Agile Coaching, Agile, Mobile Architecture, User Interface (UI), APIs, Web Architecture, Maps, Google Maps, Google Maps API, Microservices Architecture, GitHub, Minimum Viable Product (MVP), HTML5, CSS3, REST APIs, Technical Leadership, HTML, Cloud, Full-stack, Front-end Development, Front-end, Single-page Applications (SPAs), Webpack, REST, ECMAScript (ES6), Integration Testing, Object-oriented Programming (OOP), JSON, Internationalization, E2E Testing, CoffeeScript, Test-driven Development (TDD), Scrum, Continuous Delivery (CD), Continuous Integration (CI), Web App Development, Web Development, i18n, iOS API, WebSockets, CSS, Sinon.JS, Mocha, Android SDK, Android, Jasmine, Karma, Express.js, Fastlane, MacOS, Linux, Jira, OpenLayers, TypeScript, JavaScript, Docker, Node.js, Backbone.js, GIS, Mapping, GitFlow, Mobile Apps, Cordova Plugins, Cordova, Xcode, Navigation, Web Applications, Web & Mobile Applications, Web Application Architecture, SCSS, Mobile Development, PWABuilder, AWS Amplify, Monorepos, Mobile First, Web App Design, Web Design, Event-driven Architecture, NPM, Software Design, Postman, Full-stack Development, Chai, Kotlin, Ionic, Technical Architecture, Testing, TCP/IP, UX Design, UI Design, Mobile UX, Back-end Development, Git
Lead Full-stack Angular/Node.js/Java Engineer
2014 - 2015
KMD (via 7N)
- Designed and implemented the Angular front-end UI and logic layer of an enterprise citizen services application suite for Danish municipalities.
- Created and implemented a legal milestones contract BDD testing framework and CI/CD pipelines.
- Engineered a back-end security layer for REST API endpoints.
Technologies: HTTP, API Integration, Continuous Development (CD), Leadership, Agile Coaching, Agile, Responsive Web Design (RWD), User Interface (UI), XML Web Services, APIs, Web Architecture, Microservices Architecture, Model View Presenter (MVP), HTML5, CSS3, REST APIs, Technical Leadership, HTML, Cloud, Back-end, Full-stack, Front-end Development, Front-end, Single-page Applications (SPAs), NgRx, Webpack, JavaScript, Architecture, Pair Programming, ECMAScript (ES6), Integration Testing, Object-oriented Programming (OOP), JSON, SAML, Internationalization, AOP, E2E Testing, Test-driven Development (TDD), Behavior-driven Development (BDD), Scrum, Continuous Deployment, Continuous Delivery (CD), Continuous Integration (CI), Web App Development, Web Development, SQL, i18n, CSS, Sass, Sinon.JS, Protractor, Jasmine, Karma, Mockito, JUnit, jQuery, Cucumber, Jenkins, Groovy, RabbitMQ, Microservices, Spring, Hibernate, Java, Docker, Linux, TypeScript, Node.js, REST, CQRS, WildFly, Java EE 8, AngularJS, Requirements Analysis, MEAN Stack, Security, Team Leadership, GitFlow, CI/CD Pipelines, Azure PaaS, QA Testing, QA Automation, Web Applications, Web Application Architecture, SCSS, Third-party APIs, Scalability, MySQL Server, MySQL Performance Tuning, Monorepos, JavaScript Testing, System Administration, Travis CI, Puppeteer, Web Security, Web App Design, Event-driven Architecture, Selenium, NPM, RESTful Web Services, Software Design, Angular Bootstrap, Full-stack Development, Customer Relationship Management (CRM), Office Add-ins, RDBMS, API Gateways, Technical Architecture, Testing, Cryptography, Data Processing, UI Design, Java Servlets, Back-end Development, Distributed Systems, Git
Lead Developer, Software Engineer
2011 - 2014
Studio Metod Komunikacji (Self-employed)
- Designed and implemented an eCommerce integration platform for Prestashop, Alibaba, and Allegro, supporting international retail stores.
- Implemented a B2C insurance portal, including integration with an insurance company that offers comparisons.
- Designed and developed new integration testing architecture to improve quality assurance and integration test development.
Technologies: Agile, Serverless, User Interface (UI), XML Web Services, APIs, Web Architecture, SaaS, WordPress, PHP, eCommerce APIs, eCommerce, Microservices Architecture, Bitbucket, Model View Presenter (MVP), HTML5, CSS3, REST APIs, Technical Leadership, HTML, Cloud, Back-end, Full-stack, Front-end Development, Front-end, Single-page Applications (SPAs), JavaScript, Microservices, DevOps, Firebase, Integration Testing, Object-oriented Programming (OOP), JSON, Spring AOP, AOP, E2E Testing, Scrum, Continuous Delivery (CD), Continuous Integration (CI), Web App Development, Web Development, SQL, Jakarta Server Pages (JSP), CSS, Protractor, Karma, OpenVPN, Google Cloud Platform (GCP), Express.js, Java, Linux, Node.js, Mockito, JUnit, PostgreSQL, EJB3, Spring 3, Spring, JBoss, Test-driven Development (TDD), Eclipse IDE, Apache Maven, Bootstrap 3, Bootstrap, jQuery, AngularJS, MySQL, Jetty, JAXB, JAX-RPC, REST, Spring 4, JPA, Hibernate, Java EE 8, JEE, Requirements Analysis, MEAN Stack, Web Scraping, GitFlow, CI/CD Pipelines, Web Applications, Python, Software Architecture, Third-party APIs, Spreadsheets, Mobile Development, MySQL Performance Tuning, Adobe ColdFusion, Django, JAX-RS, Gradle, Jenkins, Salesforce API, Salesforce, Selenium, NPM, RESTful Web Services, Data Scraping, Angular Bootstrap, Flask, Postman, Full-stack Development, Customer Relationship Management (CRM), RDBMS, Scraping, Testing, Payment APIs, Google BigQuery, Microsoft SQL Server, Java Servlets, Back-end Development, Git
Senior JEE Developer
2010 - 2011
Leadenhall Polska S.A (Lloyd's Coverholder)
- Created an insurance policy management and integrated it with the existing core platform.
- Developed and supported B2B specialist insurance platform for international brokers from different time zones.
- Constructed a CI/CD environment and production release pipelines.
Technologies: Continuous Development (CD), Agile, Model View Presenter (MVP), REST APIs, Back-end, Single-page Applications (SPAs), REST, Integration Testing, Object-oriented Programming (OOP), i18n, JSON, Internationalization, PDF.js, Spring AOP, AOP, Scrum, Continuous Delivery (CD), Continuous Integration (CI), Web App Development, Web Development, SQL, Jakarta Server Pages (JSP), Mockito, JUnit, jQuery, Spring, Java, Linux, Node.js, Jira, Bamboo, Apache Maven, PostgreSQL, EJB3, Hibernate, Spring 3, JBoss, GWT-Ext, GWT, JEE, Requirements Analysis, GitFlow, CI/CD Pipelines, QA Testing, Web Applications, Fintech, Charts, Third-party APIs, MySQL Server, JavaScript Testing, JAX-RS, Gradle, RDBMS, Testing, Java Servlets, Back-end Development, Git
Senior JEE Developer
2007 - 2010
Efinity
- Developed a platform and back office for car insurance brokers and car dealers, and integrated it with insurance companies' external systems.
- Integrated insurance companies and insurance calculation and comparison modules.
- Designed and implemented a functional-based system to define insurance quotation modules.
Technologies: HTTP, API Integration, Continuous Development (CD), Agile, XML Web Services, APIs, Model View Presenter (MVP), REST APIs, HTML, Back-end, Full-stack, Single-page Applications (SPAs), REST, JavaScript, Pair Programming, Production Support, Technical Support, Integration Testing, Object-oriented Programming (OOP), JSON, Spring AOP, AOP, Continuous Delivery (CD), Continuous Integration (CI), Web App Development, Web Development, SQL, Mockito, JUnit, Java, Linux, Bamboo, Apache Maven, Bootstrap, jQuery, XMLBeans, Hibernate, Spring, JBoss, JEE, GitFlow, CI/CD Pipelines, QA Testing, Third-party APIs, Monorepos, JavaScript Testing, CXF, JAX-RS, Gradle, Selenium, RDBMS, Testing, Java Servlets, Back-end Development, Distributed Systems, Git
Lead JEE Developer, Architect
2003 - 2006
Mobile Entertainment Europe
- Led a team of Java developers and a web designer to design and implement a mobile content provisioning and commerce platform used by over 20,000 users.
- Created the mobile game Bobby Bearing which was licensed by the Edge Games; game sales reached a volume of 10,000.
- Designed and implemented a multiplayer scoring platform for Polish mobile network operators.
Technologies: HTTP, API Integration, Leadership, Responsive Web Design (RWD), User Interface (UI), XML Web Services, APIs, Model View Presenter (MVP), REST APIs, Technical Leadership, HTML, Full-stack, Front-end Development, Front-end, REST, Architecture, DevOps, Integration Testing, Object-oriented Programming (OOP), JSON, SAML, Spring AOP, MySQL, J2ME, Test-driven Development (TDD), Jira, Apache Maven, Hibernate, Spring, Jetty, Java, Jakarta EE (Java EE or J2EE), Requirements Analysis, Security, Web Applications, Software Architecture, Third-party APIs, Spreadsheets, Mobile App Development, Mobile Development, MySQL Server, MySQL Performance Tuning, Gamification, Search Engine Optimization (SEO), RESTful Web Services, RDBMS, Testing, Cryptography, TCP/IP, Digital Kiosks, Java Servlets, Back-end Development, Git
Java Full-stack Software Lead
2002 - 2006
Filmweb
- Created the first worldwide dynamic wireless application protocol (WAP) service. All Filmweb movie databases are available on WAP devices.
- Developed an ad-server that serves ads on the Filmweb portal to 50,000 users.
- Designed and implemented SEO features to make Google movie search results shown in the top three positions.
- Led the design and implementation of a user-based movie recommendation engine using collaborative filtering algorithms. The system analyzed user ratings for shared watched movies to provide personalized movie suggestions, enhancing user experience.
Technologies: Responsive Web Design (RWD), Video Streaming, User Interface (UI), APIs, Web Architecture, REST APIs, Technical Leadership, HTML, Back-end, Full-stack, Front-end Development, Front-end, REST, JavaScript, DevOps, Integration Testing, Object-oriented Programming (OOP), JSON, Wireless Application Protocol (WAP), MySQL, Linux, jQuery, Apache Maven, Jakarta Server Pages (JSP), Java, Web Scraping, Security, FFmpeg, Web Applications, Web Application Architecture, Third-party APIs, MySQL Server, MySQL Performance Tuning, Mobile First, Search Engine Optimization (SEO), Web App Design, RESTful Web Services, Recommendation Systems, RDBMS, UX Design, UI Design, Back-end Development, Git
Senior J2EE Developer, Team Leader
2000 - 2005
Artegence
- Designed and implemented mobile services and content platforms for the mobile network operator.
- Created and applied an inventory and logistics management platform for Lafarge Nida Gips.
- Developed and introduced an integration testing framework as a reusable framework for customer projects.
- Developed an innovative printer/scanner driver database for consumer and business end-users for HP Poland.
Technologies: Back-end, JavaScript, DevOps, Pair Programming, Integration Testing, Object-oriented Programming (OOP), JSON, Jetty, Apache Maven, Jakarta EE (Java EE or J2EE), Java, Web Applications, Mobile Development, MySQL Server, MySQL Performance Tuning, Search Engine Optimization (SEO), CXF, RDBMS, Testing, TCP/IP, Digital Kiosks, UI Design, Back-end Development
Project History
AI Agentic Software Development Framework
I architected and developed a AI-agentic framework to transform software engineering through human-AI collaboration, combining the Cline AI coding assistant with custom Electron tooling for a full specification-driven development ecosystem.
Innovation: Dedicated specification architecture achieving 60% token reduction in AI context loading, maintaining a single source of truth.
Five-phase workflow pipeline:
• Business Analysis
• Functional Requirements
• Technical Design
• Implementation Planning
• Code Generation
• Automated definition of done/ready quality gates.
• File-based memory management, hierarchical context, procedural memory via reusable workflows, and episodic memory via Git integration.
• Automated spec-sync validation tools ensuring specification-code alignment and preventing drift
Features: Progressive disclosure implementation from single-agent workflows, Plan-Act-Verify-Explain cycle automation, What/Why/How framework ensuring comprehensive requirements coverage
I integrated security-first sandbox execution with explicit tool permissions and audit trails. The framework enables 5x+ development velocity boost, 80-90% quality enhancement, systematic specification management, and automated validation gates.
Innovation: Dedicated specification architecture achieving 60% token reduction in AI context loading, maintaining a single source of truth.
Five-phase workflow pipeline:
• Business Analysis
• Functional Requirements
• Technical Design
• Implementation Planning
• Code Generation
• Automated definition of done/ready quality gates.
• File-based memory management, hierarchical context, procedural memory via reusable workflows, and episodic memory via Git integration.
• Automated spec-sync validation tools ensuring specification-code alignment and preventing drift
Features: Progressive disclosure implementation from single-agent workflows, Plan-Act-Verify-Explain cycle automation, What/Why/How framework ensuring comprehensive requirements coverage
I integrated security-first sandbox execution with explicit tool permissions and audit trails. The framework enables 5x+ development velocity boost, 80-90% quality enhancement, systematic specification management, and automated validation gates.
Doctor Ratings Based on Opinion Sentiment Scores
A browser extension to estimate more accurate ratings of doctors based on AI sentiment scores calculated from patients' opinions. The project consists of two parts:
• A BERT model trained on comments to medical appointments end an exposed endpoint to evaluate queries.
• A browser extension querying the back end
• A BERT model trained on comments to medical appointments end an exposed endpoint to evaluate queries.
• A browser extension querying the back end
POC of Drone Operations Marketplace for Mexican Agriculture Startup
I designed and implemented a mobile app proof of concept (POC) that revolutionized the agriculture industry by connecting drone fleet owners with operators. This innovative marketplace streamlined agriculture monitoring and pesticide application processes. Collaborating closely with founders and early adopters, I successfully developed a user-friendly POC application for iOS and Android devices.
This project showcases my adaptability and expertise in diverse domains. By challenging traditional norms, I developed a responsive and intuitive application that played a crucial role in agricultural operations.
This project showcases my adaptability and expertise in diverse domains. By challenging traditional norms, I developed a responsive and intuitive application that played a crucial role in agricultural operations.
Waiting Line and Order Number/Ticketing System Minimum Viable Product
Designed and implemented a minimum viable product for a waiting line ticketing system focusing on first-time UX. First-time users can use the simple-to-use yet fully functional mobile web page/PWA to avoid installing another mobile app.
Unique and innovative solutions were used to offer a seamless user experience:
• Custom QRcode generation allows embedding pictures blended over all the code areas.
• Apple Pay Wallet passes to overcome the lack of web/PWA push notifications on the iOS platform while regular.
• Human-readable dictionary-based noun-adjective proof identifiers.
Unique and innovative solutions were used to offer a seamless user experience:
• Custom QRcode generation allows embedding pictures blended over all the code areas.
• Apple Pay Wallet passes to overcome the lack of web/PWA push notifications on the iOS platform while regular.
• Human-readable dictionary-based noun-adjective proof identifiers.
DIEGY | Restaurant Review Search Mobile App
https://github.com/ciekawy/diegyAn Ionic, Elm, and GraphQL-based proof-of-concept showcase mobile/PWA app. The app's idea was to integrate the latest industry technologies and verify they could successfully work together. There was one incompatibility issue between Elm and Ionic raised to both communities with overall success, and constructive communication has started to remove the incompatibility.
SMServer: SMS Gateway
Designed and developed SMS Gateway in the early GSM/SMS era—before network-provider APIs availability (1998-2000)—initially using GSM modems installed in data centers. Product featured by network operators enrolled for a number of both DevOps and news notification cases.
Cryptocurrency Arbitrage Monitoring Tool
Developed proof-of-concept project to monitor possible arbitrage trades between different cryptocurrency exchanges including Binance, Bitmex, Deribit, and Bybit exchanges. Used Node.js and CCXT library to connect to cryptocurrency exchange APIs.
COVID-19 World Data Visualization in D3.js
Series of charts in D3.js to present stats on worldwide COVID-19 data. Variety of selectable metrics used to dynamically update data presented on:
• Worldwide maps
• Multiline charts
• Pie charts
• Grouped bar charts
• Worldwide maps
• Multiline charts
• Pie charts
• Grouped bar charts
Proof of Concept | Revolutionizing Ski Training with Sensor-driven Coaching Insights
The project aimed to develop a proof of concept for sports coaching software designed to optimize ski training using sensor-equipped inserts for ski boots. In collaboration with a team of professionals, including a renowned ski instructor who coached national-level athletes, the research analyzed foot pressure and ski angle data collected via Bluetooth. We wanted to create personalized training programs and real-time, on-slope suggestions for skiers, ultimately enhancing their performance by leveraging the expertise of a seasoned coach and advanced sensor technology.
LLM GPT-based Local Knowledge Management
This project aimed to develop a cutting-edge AI assistant that leverages the Langchain tool to create a comprehensive local knowledge base by indexing various local documents such as notes, Slack conversations, Jira tickets, and Git repositories. Our AI assistant would prepare relevant context to be used with the large language model (LLM) OpenAI API to engage in natural language conversations and effectively query the local knowledge base. Our solution combines advanced AI capabilities with user-friendly interactions to enhance knowledge sharing and retrieval within any organization.
Education
1998 - 2002
Bachelor's Degree in Software Engineering
University of Warsaw - Warsaw, Poland
Skills
Libraries/APIs
React, Node.js, RxJS, REST APIs, Claude API, OpenAI API, JAX-RS, NgRx, Facebook Login, Fabric, Sinon.JS, iOS API, Intercom API, D3.js, JAX-RPC, React Redux, FFmpeg, Puppeteer, Beautiful Soup, Chai, Java Servlets, Backbone.js, jQuery, Facebook API, X (formerly Twitter) API, Passport.js, OpenLayers, JAXB, Firebase Android SDK, Vue, CCXT, Google Maps, Google Maps API, Chart.js, Stripe, Twilio API, Firebase iOS SDK, AG Grid, AWS Amplify, Salesforce API, NumPy, Scikit-learn, Tortoise TTS
Tools
Git, GitHub, JavaScript Testing, PyCharm, Claude, IntelliJ IDEA, WebStorm, Jetty, WildFly, Fastlane, OpenVPN, Webpack, Apache Maven, Gradle, Jenkins, CircleCI, Cucumber, Jira, Karma, Capacitor, OneSignal, Mocha, Splunk, Eclipse IDE, Short Message Service Center (SMSC), Crashlytics, Bitbucket, GitLab, Xcode, Amazon Simple Queue Service (SQS), Spreadsheets, PWABuilder, Angular Universal, ChatGPT, NPM, Postman, Windsurf, Whisper, Kafka Streams, Terraform, RabbitMQ, Bugsnag, Vault, NGINX, Apple Push Notifications, Graylog, Grafana, Telegraf, Kibana, Ansible, Haystack, Travis CI, Firebase Analytics, Bamboo, Google Analytics, Firebase Authentication, Firebase Cloud Messaging (FCM), GitLab CI/CD, Figma, AngularFire, GIS, Amazon Cognito, Cordova Plugins, Amazon Simple Notification Service (SNS), Prisma, Yarn Workspaces, Amazon ElastiCache, Mongoose, Babel, Microsoft Excel, MySQL Performance Tuning, AWS AppSync, Amazon CloudFront CDN
Languages
Java, GraphQL, TypeScript, JavaScript, CSS, SQL, ECMAScript (ES6), HTML, HTML5, Python, Java EE 8, PHP, Perl, Kotlin, Groovy, Sass, CoffeeScript, CSS3, TypeScript 3, Swift, SCSS, Dart, Elm, SAML, DYNAMO, Go
Frameworks
AngularJS, Angular, Ionic 4, Ionic, Express.js, Ionic 3, XMLBeans, Selenium, Spring, Hibernate, JSON Web Tokens (JWT), JPA, Bootstrap, JUnit, Jasmine, Protractor, Appium, Jakarta Server Pages (JSP), OAuth 2, NestJS, Spring 4, Bootstrap 3, Spring 3, Spring AOP, Redux, Tailwind CSS, Yarn, Flutter, Electron, LlamaIndex, Swagger, Agentic Frameworks, LangGraph, Hapi.js, Dropwizard, CXF, Mockito, Android SDK, Cypress, Spring Boot, React Native, GWT, GWT-Ext, Jest, Material UI, Angular Material, Serverless Framework, Django, Next.js, Scrapy, Flask
Paradigms
REST, Continuous Integration (CI), Continuous Delivery (CD), E2E Testing, Object-oriented Programming (OOP), Model View Presenter (MVP), Web Architecture, Agile, Design Patterns, Continuous Development (CD), Mobile Development, Unit Testing, Testing, Microservices, Continuous Deployment, Scrum, Behavior-driven Development (BDD), Test-driven Development (TDD), CQRS, AOP, Functional Programming, Pair Programming, Microfrontends, DevOps, Microservices Architecture, Responsive Web Design (RWD), Serverless Architecture, Cross-platform, Requirements Analysis, MEAN Stack, Reactive Programming, Web Application Architecture, Lambda Architecture, Web App Design, Event-driven Architecture, Objectives & Key Results (OKRs), Kanban, Parallel Programming, Key Performance Metrics, DevSecOps, Gamification, Search Engine Optimization (SEO), UX Design, UI Design
Platforms
Docker, Google Cloud Platform (GCP), JEE, Mobile, Jakarta EE (Java EE or J2EE), J2ME, AWS Lambda, Linux, Parse Server, Android, PagerDuty, Apple, iOS, JBoss, PDF.js, Firebase, Amazon Web Services (AWS), Backendless, LocalStack, MacOS, WordPress, New Relic, KVM, Mailgun, Visual Studio Code (VS Code), Kubernetes, Apache Kafka, Twilio, Azure PaaS, Amazon EC2, Adobe ColdFusion, Salesforce, Azure, Vercel, RevenueCat, Blockchain
Storage
Databases, JSON, RDBMS, MongoDB, MySQL, PostgreSQL, NoSQL, Amazon S3 (AWS S3), MySQL Server, Database Migration, Datadog, Elasticsearch, InfluxDB, Redis Cache, Google Cloud, Redis, Firebase Realtime Database, Cloud Firestore, Amazon DynamoDB, PostGIS, Microsoft SQL Server
Industry Expertise
Web Design, Accounting
Other
Web Development, Web App Development, Wireless Application Protocol (WAP), Software Engineering, Algorithms, Data Structures, Integration Testing, Progressive Web Applications (PWAs), Single-page Applications (SPAs), Front-end, Front-end Development, Full-stack, Back-end, APIs, Mobile App Development, API Integration, Web Scraping, Mobile Apps, CI/CD Pipelines, Web Applications, Web & Mobile Applications, Third-party APIs, Data Scraping, Software Design, Full-stack Development, Scraping, Data Processing, ChatGPT API, ChatGPT Prompts, AI Chatbots, AI-generated Code, AI-augmented Software Engineering (AIASE), Cursor AI, Back-end Development, Anthropic, Prompt Engineering, Retrieval-augmented Generation (RAG), Workflow, Workflow Automation, Workflow Automation & System Integration, Generative Artificial Intelligence (GenAI), Private NPM Modules, Apollo, WebSockets, Push Notifications, OAuth, i18n, Lean Startups, User Metrics, SMS, SMS Gateways, Internationalization, Technical Support, Production Support, Architecture, PWA, Cloud, Technical Leadership, Minimum Viable Product (MVP), XML Web Services, Early-stage Startups, Mobile Architecture, Serverless, QR Codes, Apollo Server, Startups, Google Play Store, App Store, HTTP, Cross-platform App Development, Application State Management, Security, Team Leadership, GitFlow, Cordova, Lambda Functions, QA Testing, QA Automation, Data Visualization, Charts, Software Architecture, Headless Software, Travel, Scalability, Extensions, Artificial Intelligence (AI), GitHub Actions, Monorepos, Mobile First, Incident Management, Site Reliability Engineering (SRE), OpenAI GPT-3 API, OpenAI GPT-4 API, Language Models, LangChain, Plugins, Web Security, Chrome Extensions, RESTful Web Services, Angular Bootstrap, Customer Relationship Management (CRM), Natural Language Processing (NLP), Recommendation Systems, API Gateways, Technical Architecture, JetBrains IDE, Serial Communication, TCP/IP, Payment APIs, OpenAI, AI Agents, Agentic AI, Embedding Models, Large Language Models (LLMs), Pgvector, Supabase, FastAPI, AI Consulting, AI-enabled Applications, AI-enabled Search, App UX, Mobile UX, Serverless GPUs, AI Integration, Distributed Systems, Audio Processing, Video & Audio Processing, Video Processing, ElevenLabs Solutions, Speech Recognition, Speech-to-Text (STT), Text-to-Speech (TTS), TypeORM, Web Components, Intercom, Google Login, UXCam, EJB3, Analytics, Mobile Analytics, A/B Testing, Algebra, Cryptocurrency, eCommerce, eCommerce APIs, SaaS, Maps, User Experience (UX), User Interface (UI), Video Streaming, Google Cloud Functions, Agile Coaching, Geolocation, Leadership, Apple Pay, OpenStreetMap, Akita, Mapping, CTO, AWS DevOps, Navigation, Fintech, Amazon RDS, Machine Learning, BERT, Apple Numbers, Bluetooth, Internet of Things (IoT), System Administration, FAISS, Health, Sports, Drones, Office Add-ins, Chatbots, AWS NAT Gateway, Okta, Cryptography, Digital Kiosks, Google BigQuery, Tailwind UI, Real-time Data, Finance, Real-time Audio Processing, Crypto, Video Codecs
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