Jonathan Mlynarczyk

I was responsible for the complete takeover and transformation of a Flutter PoC into an industrial multi-software critical platform for parking management and heavy goods vehicle booking, including payment processing. This was during a development process rich in new business needs and requiring complete mastery of the technical chain. I worked on several layers of the product's overall architecture:

- Front-end Architecture of the main application: Merging and modernizing separate Flutter Mobile/Web codebases. Design and development of several interfaces for different user types (clients, managers, service providers, administrators, etc.), integrating all business functionalities, replacing the EPR by integrating billing, accounting, and back-office functions within the application. Implementation of CI/CD pipelines.

- Security and Permissions: Implementation of a rigorous and granular permission system via Firestore Rules and Custom Claims for access compartmentalization.

- Event-driven Back-end (GCP, Firebase, Node.js microservices, IoT): Structuring the microservices layer around an event-driven architecture (EventArc, Pub/Sub, gRPC) to manage complexity and operational reliability. Security via Firestore Rules, Custom Claims. Managing the interface with IoT control equipment via MQTT channels for automating vehicle entry/exit processes. GCP optimization needs (cold starts).

- Advanced Payment Systems (Embedded / POS): Development of an embedded Flutter application on an Android payment terminal, utilizing native SDKs for secure payment and bank card reading operations and PIN code management. Integration of critical gateways (Stripe, Shift4) and fuel cards and toll devices.

Sale of private label cosmetic products on an e-commerce platform.

As co-founder, I was involved in the technical and operational aspects of the company:

- Web development: continuous integration of the e-commerce platform on Shopify, including specific development of proprietary modules & sections (HTML & CSS), and creation of an API and server-side analysis features (Node.js + MongoDB).

- Operations: management of administrative, legal, and regulatory aspects, structuring and implementation of the supply chain, warehousing, and delivery to end customers, establishment and execution of financial & accounting reporting and analysis processes.

EcoCO2 is a company that offers services and connected objects for energy management improvement.

I was involved in creating the application to configure a connected object related to energy consumption.

Flutter Development:

- Integration of mockups designed in Adobe XD

- Modification of Wi-Fi connection to interact with the connected object

- Development of a module for generating encrypted data for exchange via Socket

The application is currently available on the Play Store and soon on the App Store.