Universal Fit
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Portable workout JSON

Any plan. Any author. One app to train it.

Universal Fit turns workout-plan JSON into a beautiful offline training program, whether it came from a coach, a friend, or an LLM.

Why it exists

The plan is the product.

Most fitness apps lock workouts inside proprietary editors. Universal Fit treats the plan as a portable file and focuses the app on rendering, tracking, and validating it well.

Bring your own plan

Import JSON from a coach, a spreadsheet exporter, a GitHub repo, or a prompt you gave your favorite LLM.

Track it offline

The mobile app keeps plans, active sessions, and performed logs on-device.

It is just JSON

Strict schema validation means plans are inspectable, shareable, versionable, and easy to fix when an LLM gets a field wrong.

Builder

Create or reshape a workout in the browser.

The authoring page now supports guided plan creation, pasted JSON editing, schema validation, downloads, and AI edit prompts for deeper workout changes.

Build from controls

Choose the focus, level, duration, schedule, rest, equipment, and units to generate a valid starter plan.

Paste existing JSON

Load a plan schema into quick-edit controls, adjust the workout, and keep the file valid before import.

Ask for bigger changes

Copy a focused AI prompt that includes the current plan and schema rules when a change needs judgment.

Inside the app

A familiar training surface around an open format.

Start a planned session, log sets, keep rest timers alive, and compare what you performed against what was prescribed.

Strict imports

Unknown fields are rejected and errors are written so they can be pasted back into an LLM.

Plan overview

Weeks, days, mesocycles, deloads, and session previews stay readable on a phone.

Session tracking

Set logging, quick edits, freestyle sessions, and progress history are built around actual training.

Multi-modality

Strength, cardio intervals, steady runs, mobility, and bodyweight work live in one schema.

Universal Fit mobile app screen
Universal Fit mobile app screen

App screens

Real Universal Fit screens, not placeholder fitness art.

The public site now shows the same dark training surface users see when they import, generate, track, and tune their plans.

Universal Fit library screen showing searchable workout plans.

Library

Find current, past, and archived plans from one compact shelf.

Universal Fit import plan screen showing example workout cards.

Import plans

Preview example plans, import from a file, or paste JSON directly.

Universal Fit custom plan screen showing the AI prompt workflow.

AI plan flow

Copy a structured prompt, ask an assistant, then paste the JSON back into the app.

Universal Fit history screen showing training calendar and streak stats.

History

Review weekly streaks, PRs, cardio, volume, and calendar progress.

Universal Fit settings screen showing units and plate controls.

Settings

Keep units, body weight, available plates, language, and workout preferences close.

Examples

Start with real JSON examples.

The site ships with a small static catalog first. Later the same loader can index a full curated plan library.

Open project

Support and roadmap live on GitHub.

The public site points users into structured issue forms for bugs, feature ideas, schema feedback, and plan submissions.