Juhana Leinonen

Freelancing with direct clients and as a subcontractor.

Order management system (2014-ongoing) (React, Node.js, TypeScript, JavaScript, MySQL, MongoDB, Docker)

A order management system for a company in the health and social services field, including order entry and administration, reporting, importing from a third-party ordering system, generating invoices and payroll lists, SMS sending and receiving, and management of customer payment commitments.

Online store development and maintenance (2013–2018) (PHP, Wordpress, Woocommerce)

Interactive GenAI web application (2022-2024) (React, Node.js, Firebase, GenAI service APIs incl. OpenAI, Anthropic, Deepgram, Claude)

The project implemented a React-based web application framework related to workplace coaching, which allows coaches to create and script interactive exercises and similar mini-applications for their clients. The application integrated several external GenAI services related to text generation as well as speech production and speech recognition. Firebase was used as the backend services. A Node.js-based proxy server was implemented for external services. I was responsible for implementing the initial React application, Firebase infrastructure and the proxy server.

Animal welfare association foster care coordination system (2026–) (React, TypeScript, Firebase, Google Cloud, Material UI)

A web application for the an animal Welfare association to coordinate foster care operations for homeless animals. The system is used to manage foster animal and foster home information records.

Full stack projects, development and maintenance (Typescript, Node.js, PostgreSQL, MongoDB, Wordpress)

112 Suomi mobile application (React Native, TypeScript, JavaScript, Firebase, Google Cloud, Docker, Play Store, App Store)

The official application of the national Emergency Response Centre, with approximately one million users in Finland (approx. 20% of the population.) Between 2018 and 2020 the application was completely rebuilt using React Native. My primary role was mobile application development (in a team of 2–3 developers) and partly backend development (Node.js, NestJS, Python, Google Cloud).

Shift management system for freelance workers (React, Node.js, React Native, TypeScript, JavaScript, PostgreSQL, AWS, Docker)

A React Native mobile application used by freelance workers to book work shifts, and a web application for managers to approve the shift requests. The system was taken over from a previous developer team. The mobile application, backend, and manager web application were ultimately rebuilt from scratch. I was the technical lead in a team of 2–5 developers.

Online gaming websites development and maintenance (PHP, MySQL, MongoDB, DocumentDB, Serverless, JavaScript, Node.js, AWS, Docker, Elasticsearch, Redis/Valkey, OAuth)

Development and maintenance of web-based gaming services (including a fantasy sports game and HTML5 games website.) Primary responsibility for technical maintenance and development of new features. Work also included server maintenance and architecture (AWS) and support for infrastructure modernization projects.

Development and maintenance of an order management system

Project management and managerial duties

Member of the board of directors

Occupational safety manager