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Browser Overview

Build with a Browser

Loop 3 can be built with a web browser using GitHub Actions and installed on your phone using the TestFlight app. This method works on any device with a browser (PC, Mac, tablet, or iPad) - no Mac computer required.

Same App, Different Method

  • If you prefer to use Xcode on your Mac, see Build with Mac
  • As long as you use the same Apple Developer account, the app you build is identical regardless of build method
  • When you install the app on your phone, settings and history are preserved; pump and CGM remain attached; selected Services are maintained

Is This Method Right for You?

Choose Browser Build if:

  • You don't have a Mac or prefer not to use one
  • You want automatic monthly builds (after initial setup)
  • You're comfortable following step-by-step instructions with multiple accounts (Apple, GitHub)
  • You can dedicate 2-4 hours for first-time setup (spread over several days)

Choose Mac Build if:

  • You already have an up-to-date Mac and are comfortable with Xcode
  • You prefer building locally without cloud services
  • See Build with Mac for Mac requirements

Requirements

Phone, CGM and Pump

To use the Loop app, you need:

Accounts

To build the Loop app using a browser, you need:

  1. Free GitHub account: (instructions found at New GitHub Account)
  2. Paid Apple Developer account: ($99/year; instructions found at Apple Developer Account)

Getting Started: Two Paths

Choose the path that matches your experience level:

Follow the detailed instructions below with screenshots, explanations, and help at every step.

Start here: Introduction and Summary

🔵 Path 2: Quick Reference (For Experienced Users)

If you're comfortable with GitHub and Apple Developer portals, use the condensed version:

Step-by-Step Build Process

The following pages guide you through the complete browser build process:

  1. Introduction and Summary
  2. Collect Secrets
    • Some from Apple
    • Some from GitHub
  3. Prepare Fork
  4. Prepare Identifiers
  5. Prepare App
  6. Prepare TestFlight Group
  7. Build the Loop App

After Building: Next Steps

Once your build completes successfully:

  1. Install on Phone - Use TestFlight to install the app on your iPhone
  2. Update/Rebuild - Learn how to update your app (much easier than initial build!)
  3. Build Other Apps - Optional: Build LoopCaregiver, LoopFollow, or other apps using the same setup

Need Help?

Stuck? Don't Get Frustrated!

First-time setup involves many steps across different websites. If something isn't working:

→ Get Help from Mentors

Just provide your GitHub repository link and a brief description. Mentors can view your logs and guide you.

Common troubleshooting resources:

Please DON'T...

  • Search Google or ask ChatGPT about your error
  • Spend hours frustrated
  • Delete your repository or GitHub account
  • Remove your app from App Store Connect

→ Ask a mentor instead! They can quickly diagnose issues from your repository link.

Additional Topics

Automatic Updates

Check Status of Build Action Monthly

The automatic build actions should occur every Sunday. They do for all OS-AID apps except for Loop, and even for Loop, some people are getting automatic builds. (We do not know why.)

  • Keep your Apple Developer account active
  • Install updates from TestFlight when ready
  • Note: Starting May 2025, you may need to manually trigger builds every 60 days

Learn more: Automatic Update & Build

Customization

Want to customize your Loop app? Both methods are supported:

Development Version

For advanced users who want cutting-edge features before official release:

Build Stable First

We recommend building the stable release version first. Once successful, you can switch to the development version.

Comparison: Browser vs Mac Build

Feature Browser Build Mac Build
Device Required Any device with browser Mac with recent macOS
Xcode Required No (GitHub provides) Yes (must update regularly)
Initial Setup Time 2-4 hours over several days 1-2 hours (if Mac is ready)
Monthly Updates Automatic or
Five minutes with Manual Actions
Build uploaded to TestFlight		 Manual via Xcode
Build Time ~30 minutes (in cloud) ~30 minutes (local)
App Expiration 90 days (TestFlight) 1 year
Customization Supported Supported

Build Frequently Please check monthly to see if there is a newer version of the Loop app.

  • Sometimes there is a new feature
  • Sometimes there is a required update to support the latest phone iOS
  • Even though a Mac lets you go a year between builds, you should build at least once a quarter

Both methods produce the identical Loop app. Choose based on your available hardware and preferences.