Krystian Hanek

vise DMW is an advanced, web-based platform for data management, ETL processes, and data quality assurance, designed to streamline data migrations, transformations, and validations. vise LoV-Map is a value mapping and alignment tool that enables management of mapping tables and business value relationships. Designed and maintained backend services and authorization mechanisms for this production platform. Owned cloud infrastructure using AWS CDK to support secure deployments, horizontal scaling, and stable runtime environments. Implemented reporting components tightly coupled with backend domain logic.

SaaS Boilerplate is a ready-to-use, customizable, and well-tested open-source toolkit that provides all essential components to build a complete SaaS product. The platform offers out-of-the-box features including authorization and authentication, email management, subscriptions, payments, multitenancy, CMS integration, and OpenAI integration. Built on React, TypeScript, Python, and AWS, with infrastructure-as-code and pre-configured CI/CD. Introduced backend observability by integrating Prometheus and Grafana, enabling deeper insight into application behavior, performance bottlenecks, and error patterns in production.

Kandua is South Africa's leading home services platform, the world's first AI-powered home services platform that connects homeowners with vetted professionals. The platform offers services from electricians, plumbers, and other specialists, leveraging AI to diagnose user needs and match them with appropriate professionals. Designed backend architecture and data flows for this serverless, microservice-based system. Implemented inter-service communication, domain-driven service boundaries, and integrations with external providers (payments, utilities, emergency services).

Virtual Expo Dubai 2020 was the first virtual rendition of the world's biggest event - the World Expo. A 6-month virtual experience that enabled visitors from around the world to access events, talks, performances, and architecture from 192 participating countries without traveling to Dubai. The platform featured an accurate digital replica of the massive Expo site with country and thematic pavilions, day and night modes, and over 200 custom-made 3D pavilions. Implemented backend features including database schema evolution, API development, and AWS Elasticsearch integration. Focused on data querying, performance, and maintainability in a TypeScript-based backend.

QuestPass is an advertising platform based on an innovative "questvertising" format that guarantees 100% attention and understanding of the advertising message by requiring users to answer a question related to the ad content before accessing content. The platform connects advertisers, publishers, and viewers, offering advertisers assurance that their ads have been seen and consciously understood, publishers the ability to monetize valuable content, and viewers free access to premium materials. Backend systems supporting the platform by introducing new media types (video), integrating AWS MediaConvert, and enhancing reporting and analytics endpoints. Optimized backend systems to handle high and unpredictable traffic peaks through caching strategies, architectural improvements, and systematic load testing. Designed and executed performance and stress testing scenarios.

LESS_ was a Polish social platform and mobile application for buying and selling used clothing, shoes, and accessories, promoting the idea of circular fashion and wardrobe refresh. It functioned as a "virtual wardrobe", combining features of Instagram and OLX/Vinted-style marketplace, with emphasis on transaction security. The platform enabled users to browse others' wardrobes, follow profiles, and buy and sell clothing, supporting the idea of reducing consumption through second-hand clothing trade. Built and evolved backend APIs for personalized content, payments, and verification workflows. Implemented and later migrated authentication mechanisms (Auth0 → custom solution). Improved system resiliency through backend optimizations and comprehensive testing.