How Many Shiny Apps Can You Host for Free?

Shiny is an incredible piece of technology. The ease of which with you can make simple prototypes or even production-grade applications is unparalleled. All you need is a bit of R skills.

But all this is worthless unless you can present your app to your users. If you are just starting out, you don’t need any headaches with deployment. You also probably don’t want to pay big bucks for hosting either.

So what are your options for free Shiny app hosting? And how many apps can you host for free?

Hey, #rstats folks! Do you know how many #shiny apps can you host for free ($0)?

— Péter Sólymos (@psolymos) December 10, 2021

I ask this question on

Try pulling ad running the Docker image analythium/correlation:v3:

docker pull analythium/correlation:v3

docker run -p 4000:3838 analythium/correlation:v3

You’ll find two apps on the following two paths: http://localhost:4000/app2d/ and http://localhost:4000/app3d/. The Dockerfile looks like this:

FROM rocker/shiny:4.0.5

## install dependencies
RUN install2.r -r http://cran.rstudio.com/ rgl

## copy the apps
COPY ./app-v1.R /srv/shiny-server/app2d/app.R
COPY ./app-v2.R /srv/shiny-server/app3d/app.R

USER shiny
EXPOSE 3838
CMD ["/usr/bin/shiny-server"]

In theory, there is no limit to the number of apps you can host simultaneously using this setup.

Conclusions

It turns out that most respondents were right in their own ways because I left many details undefined. Shinyapps.io is the platform that R and Shiny users are most familiar with. This is due to the RStudio IDE integration and most tutorials pointing to this free option. So that is your 5 free apps.

If you need to host more Shiny apps, sign up with your other email address to get another 5 apps for free. Or learn how to dockerize Shiny apps and deploy to Heroku and Fly.io under the free tier. Fly.io is your best option if you want the apps running 24/7 and under a secured custom domain (none of this is offered for Shinyapp.io and Heroku).

If you run out of email addresses and exhausted all your free apps, you can consider including multiple apps in the same Docker image and deploy these to Heroku and Fly.io. Those who chose  ‘As many as you like’ were probably thinking along these lines. 108 times many times unlimited is a lot!

Further reading