RoutineTrainer.com

Business context

Coaches typically run client management, programming and billing across several disconnected tools. RoutineTrainer replaces that with one platform that separates the coach's operational view from the client's experience.

The challenge

Build a single, coherent platform covering authentication, role-based access, client onboarding, workout and nutrition plans, subscription billing and messaging — without any one workflow compromising the others.

Objectives

• Separate coach and client roles with distinct, secure access.
• Structure onboarding so new clients reach an assigned plan with minimal friction.
• Support workout and nutrition plan creation, assignment and tracking.
• Handle subscription billing as a core part of the platform, not an add-on.
• Provide messaging between coach and client inside the platform.

Role & responsibilities

Full-stack design and development across the API and the client application, including authentication, billing integration and the coach and client workflows.

• API design and development (ASP.NET Core)
• Database design and data access (PostgreSQL, EF Core)
• Authentication and role-based access control
• Subscription billing integration
• Workout and nutrition plan features
• Client messaging and document flows
• Frontend application (React) and its integration with the API

Solution overview

A .NET API handles accounts, plans, billing and activity data behind token-based authentication, while a React client gives coaches and clients separate, role-appropriate views. Subscription billing, messaging and document handling are built into the platform rather than bolted on.

What was built

Architecture & technology

An ASP.NET Core Web API (.NET 8) backed by PostgreSQL through Entity Framework Core, with token-based authentication and dedicated controllers for authentication, admin, billing, workouts, nutrition and activity logs. The React frontend is a separate application built with Vite and TypeScript, communicating with the API over HTTP.

Backend

• ASP.NET Core 8 (C#)
• Entity Framework Core
• PostgreSQL
• ASP.NET Core Identity
• JWT authentication
• FluentValidation

Billing & messaging

• Stripe
• SendGrid
• Twilio
• Resend

Frontend

• React
• Vite
• React Router
• TypeScript

Storage & data

• Vercel Blob

Design decisions

Separate coach and client surfaces

Coaches and clients see different views built around what each role actually needs to do, rather than one shared dashboard with permissions layered on top.

Technical challenges

• Coordinating authentication, subscription billing and messaging across a separate API and frontend application as one coherent product
• Structuring workout, nutrition and client data so coach and client workflows stay independent but connected

Current status

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