Building Scalable Web Apps

A Shiny app running on your laptop is only useful to you. This final lesson covers taking your app from localhost to a live, publicly accessible production deployment.

1. Testing Locally First

# In RStudio, with app.R open:
shiny::runApp("path/to/your/app")

# Or simply click "Run App" in the RStudio toolbar

2. Deployment Option Overview

3. Deploying to shinyapps.io (Fastest Path)

Step 1: Create an Account

Sign up for free at shinyapps.io.

Step 2: Install and Configure rsconnect

install.packages("rsconnect")
library(rsconnect)

# Copy your token/secret from the shinyapps.io dashboard
rsconnect::setAccountInfo(name = "your-account-name",
                           token = "YOUR_TOKEN",
                           secret = "YOUR_SECRET")

Step 3: Deploy Your App

rsconnect::deployApp("path/to/your/app")

RStudio will upload your app, install required packages in the cloud, and give you a live public URL like https://your-account.shinyapps.io/your-app/.

4. Setting Up Your Own Shiny Server (Linux)

# On an Ubuntu server
sudo apt-get install gdebi-core
wget https://download3.rstudio.org/ubuntu-18.04/x86_64/shiny-server-1.5.20.1002-amd64.deb
sudo gdebi shiny-server-1.5.20.1002-amd64.deb

# Place your app in the default directory
sudo cp -R my_shiny_app /srv/shiny-server/

# Access it at http://your-server-ip:3838/my_shiny_app/

5. Managing Dependencies for Deployment

Use renv to lock exact package versions so your deployed app behaves identically to your local development environment:

install.packages("renv")
renv::init()       # creates a project-local library and lockfile
renv::snapshot()   # records exact package versions in renv.lock

6. Performance Tips for Production Apps

• Use reactive() and eventReactive() to avoid redundant recalculation.
• Pre-aggregate large datasets outside the app where possible, rather than on every reactive trigger.
• Enable caching with bindCache() for expensive, repeatable computations (Shiny 1.6+).
• Monitor app logs on shinyapps.io or Shiny Server for errors and slow response times.

7. Production-Ready Checklist

• ✅ Test thoroughly locally — before deploying anywhere.
• ✅ Choose the right platform — shinyapps.io for speed, Shiny Server for full control.
• ✅ Lock dependencies with renv — for consistent, reproducible deployments.
• ✅ Never hardcode secrets — use environment variables instead.
• ✅ Optimize reactivity — for a smooth experience under real user load.