Dynamic Apps

Apps are content items that stay running to serve requests. Unlike tasks, which execute once and then stop, an app keeps a process alive to handle incoming HTTP traffic. Examples are a Shiny dashboard, a Plumber API, or a FastAPI service. Ricochet manages app processes for you, including scaling them up and down based on demand.

See the content items overview for the full list of supported app types.

How apps work

When an app is deployed, ricochet starts its entrypoint script and expects the process to bind to a port. Ricochet routes incoming HTTP requests to the running process. If the app crashes, ricochet restarts it automatically.

Apps scale horizontally by spawning additional instances when connection thresholds are reached. Configure scaling behavior in the ricochet web UI or via the [serve] settings in your _ricochet.toml.

R apps

Shiny

Shiny apps are interactive web applications. Use the content type shiny (or shiny-r).

The entrypoint can be a single app.R file or a directory containing ui.R and server.R.

[content]
name = "My Shiny App"
entrypoint = "app.R"
content_type = "shiny"

Shiny documents

R Markdown and Quarto documents that use a Shiny runtime are deployed as apps rather than tasks because they require a live R process.

Content Type	Description
rmd-shiny	An R Markdown document with runtime: shiny in its YAML header.
quarto-r-shiny	A Quarto document with a Shiny runtime.

[content]
name = "Interactive Report"
entrypoint = "report.Rmd"
content_type = "rmd-shiny"

Plumber

Plumber converts R functions into RESTful API endpoints using special comments.

[content]
name = "My Plumber API"
entrypoint = "plumber.R"
content_type = "plumber"

Ambiorix

Ambiorix is a web framework for R inspired by Express.js. It can serve both web applications and APIs.

[content]
name = "My Ambiorix App"
entrypoint = "app.R"
content_type = "ambiorix"

Serverless R

The serverless-r content type lets you deploy plain R functions as a REST API without writing any web framework code.

R Service

The r-service content type is a generic option for R web apps or APIs that don’t fit the other categories. ricochet runs your entrypoint script directly. Start your server on the host and port in the HOST and PORT environment variables.

[content]
name = "Custom R App"
entrypoint = "app.R"
content_type = "r-service"

Python apps

FastAPI

FastAPI is a modern Python web framework for building APIs. Ricochet launches FastAPI apps with uvicorn.

[content]
name = "My FastAPI App"
entrypoint = "app.py"
content_type = "fast-api"

Flask

Flask is a lightweight Python web framework for building web apps and APIs.

[content]
name = "My Flask App"
entrypoint = "app.py"
content_type = "flask"

Streamlit

Streamlit is a framework for building data apps in Python with minimal code.

[content]
name = "My Streamlit App"
entrypoint = "app.py"
content_type = "streamlit"

Dash

Dash is a framework for building analytical web applications in Python.

[content]
name = "My Dash App"
entrypoint = "app.py"
content_type = "dash"

Shiny for Python

Shiny for Python brings the Shiny framework to Python for building interactive web apps.

[content]
name = "My Shiny App"
entrypoint = "app.py"
content_type = "shiny-py"

Python Service

The python-service content type is a generic option for Python web apps or APIs. ricochet runs your entrypoint script directly. Start your server on the host and port in the HOST and PORT environment variables.

[content]
name = "Custom Python App"
entrypoint = "app.py"
content_type = "python-service"

Python App

Use the python-app content type for interactive Python web apps that keep a live connection to each browser, such as Panel. ricochet runs your entrypoint script directly and counts each open browser session as one connection. Start your server on the host and port in the HOST and PORT environment variables.

[content]
name = "My Panel App"
entrypoint = "app.py"
content_type = "python-app"

Julia apps

Genie

Genie apps, including those built with Stipple or GenieFramework, deploy with the genie content type. Start the server on the port in the PORT environment variable.

[content]
name = "My Genie App"
entrypoint = "app.jl"
content_type = "genie"

Julia Service

The julia-service content type deploys Julia web apps and APIs built with HTTP.jl or Dash.jl, for example. Start your server on the host and port in the HOST and PORT environment variables.

[content]
name = "My Dash.jl App"
entrypoint = "app.jl"
content_type = "julia-service"

Deployment and configuration

See the deployment guide to deploy apps with the CLI or git integration. For project requirements, see the guide for your language:

• R
• Julia
• Python