Integrating a FastAPI (Python) app within an Aspire application

Aspire sample

File-based AppHost

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This sample demonstrates integrating a FastAPI (Python) app and a JavaScript frontend using Aspire.

C#JavaScriptNode.jsPython

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AppHost

The entry point that composes every resource and dependency in this sample's distributed application.

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#:sdk Aspire.AppHost.Sdk@13.4.0
#:package Aspire.Hosting.JavaScript@13.4.0
#:package Aspire.Hosting.Python@13.4.0
#:package Aspire.Hosting.Redis@13.4.0

var builder = DistributedApplication.CreateBuilder(args);

var cache = builder.AddRedis("cache");

var app = builder.AddUvicornApp("app", "./app", "main:app")
    .WithUv()
    .WithExternalHttpEndpoints()
    .WithReference(cache)
    .WaitFor(cache)
    .WithHttpHealthCheck("/health");

var frontend = builder.AddViteApp("frontend", "./frontend")
    .WithReference(app)
    .WaitFor(app);

app.PublishWithContainerFiles(frontend, "./static");

builder.Build().Run();

The sample consists of two apps:

app: This is a simple FastAPI-based Python app that returns randomly generated weather forecast data.
frontend: This is a Vite-based React app that renders the weather forecast data.

Prerequisites

Aspire development environment
Python - at least version 3.13
Node.js - at least version 22.21.1
.NET 10 SDK

Running the app

If using the Aspire CLI, run aspire run from this directory.

If using VS Code, open this directory as a workspace and launch the apphost.cs C# file using either the Aspire or C# debuggers.

Preview

Sample screenshots

Select the image to zoom in.

Screenshot of the weather forecast frontend in the Integrating a FastAPI app within an Aspire application sample (light theme)