Bellos — Workout Planning & Tracking

Bellos began with my own experience using another fitness tracking app. I liked the training approach, but the app was not the experience I wanted. Rather than keep working around that mismatch, I built my own workout planner and logger: GetFit.

I shared GetFit’s early code as open source and developed it into a single-user application with a reusable training engine. That engine became the foundation for Bellos. The progression from a personal tool to a product meant separating the training rules from the interface, so the same core could support a more complete application.

The reusable engine implements Accordion Training™, Bellos’s training method: heavy days focus on fewer lifts, light days open up to more variety, and progression follows what was actually logged. Four-week blocks rotate heavy, moderate and light sessions, with a lighter final week. The engine brings together the exercise catalog, plan generation and training history. My work included defining the behavior, developing the implementation and documenting an engine that another application can build on.

Bellos builds on that foundation as a multi-user, installable web application. I developed the React and TypeScript interface, on-device storage with IndexedDB/Dexie, and a Node.js backend using Hono and PostgreSQL for accounts and synchronization. Workout logging saves locally and background sync connects devices. The product also includes data export, account settings and feedback flows—work beyond the landing page or an isolated interface mockup.

I designed the experience around the moment someone is training: open Today, see the planned session and last time’s numbers, log the set, and keep moving. The plan view explains the shape of a block, while progress and movement history make earlier work visible. My role spans product direction, training-engine development, full-stack implementation, interface design and the Bellos identity and website.

The gallery opens with the live Bellos landing page, followed by four in-app views captured from a standalone sample build: Today, the training block, set logging and progress. The sample uses a fictional lifter and made-up workout history, with no live account or backend connection. Bellos is my own product, currently presented as a private beta; these images demonstrate its interface and workflow rather than customer results.

Explore Bellos · GetFit and the reusable training engine