Coeus Health

Leanr Android App + WeightBox API

"Eight Bit Studios always felt like they valued what we were doing. They believed in it almost as much as we did... The completed Android app has received positive feedback with regard to the look, feel, and usability."

Dr. Kate Wolin
Founder & Professor

From Hypothesis to Health Habit: How Eight Bit Helped Coeus Build Leanr from the WeightBox API Up

Coeus Health unlocks the tools to deliver health and wellness programs that actually work. With a focus on combatting overweight and obesity at scale, their digital health APIs translate evidence-based interventions into scalable, market-ready solutions. By bridging science and software, Coeus enables the broader dissemination of clinically validated behavior change tools.

Overview

Coeus Health approached Eight Bit Studios to bring a behavioral science-backed hypothesis to life: Could personalized, qualitative feedback drive better outcomes in weight loss? What began as a project to build an intelligent feedback API (WeightBox) grew into a full-fledged Android mobile app called Leanr—intended for clinical trials and employer wellness pilots.

Ask

Build a cost-effective yet powerful Android MVP that demonstrated the viability of a weight loss intervention powered by behavioral science. Coeus needed to translate a paper-based model into a scalable mobile platform using a new API, sync it with wearable data, and test it within a real-world clinical trial.

Solution

Eight Bit Studios collaborated closely with Coeus to deliver a deeply integrated, research-backed digital product.

  • Designed and developed the WeightBox API for real-time health feedback based on rules and user data

  • Built an Android MVP app that integrated with Fitbit and other wearables to track progress and deliver daily encouragement

  • Developed branded UI, icons, and interactions that matched the tone of qualitative support—friendly, informative, and motivational

  • Provided thorough documentation and API testing for integration clarity and future extensibility

Results

The MVP laid the groundwork for broader trials and demonstrated early success with usability and engagement.

  • 100% task completion in usability testing with zero critical errors

  • Praised for intuitive design and engaging interface by testers and stakeholders

  • Successfully deployed in a controlled clinical trial, enabling side-by-side comparison of Leanr Lite vs Leanr Full

  • Enabled employer-group pilots with scalable affiliate user structures and registration code flows

Our Approach

Phase 1: Build the Foundation – WeightBox API

Eight Bit designed and launched a new feedback engine that translated behavior change logic into real-time messaging.

  • Rules-based engine that calculated goals and feedback using diet, exercise, and weight data

  • Human API integration for syncing third-party device data

  • Admin tools for managing user content and progress visualization

Phase 2: Build the MVP App – Leanr Android

The team created a native Android app for real-world deployment in a research context.

  • Streamlined flows for registration, goal-setting, and self-monitoring

  • API-driven content delivery for goal-based feedback

  • Visualizations to show progress and achievements over time

  • Fitbit API integration, custom-built in Rails due to lack of mobile SDK

Phase 3: Iterate and Expand – Full Leanr App

With new funding and trial validation, Leanr expanded into a full feature set including affiliate-level reporting and tailored engagement.

  • Google Firebase tracking for usage metrics and engagement monitoring

  • Validic and expanded Human API integrations for additional device support

  • Admin-triggered messages and automated notifications based on user behavior