What's new in Aspire 13

📢 Aspire 13 represents a major milestone in the Aspire product line.

Aspire is no longer ”.NET Aspire” - it’s now simply Aspire, a full polyglot application platform. While Aspire continues to provide best-in-class support for .NET applications, version 13.0 elevates Python and JavaScript to first-class citizens, with comprehensive support for running, debugging, and deploying applications written in these languages.

This release introduces:

• First-class Python support: Support for Python modules, deploy with uvicorn, flexible package management (uv, pip, or venv), and generate production Dockerfiles automatically.
• First-class JavaScript support: Vite and npm-based apps with package manager auto-detection, debugging support, and container-based build pipelines.
• Polyglot infrastructure: Connection properties work in any language (URI, JDBC, individual properties), certificate trust across languages and containers.
• Container files as build artifacts: A new paradigm where build outputs are containers, not folders - enabling reproducible, isolated, and portable builds.
• aspire do: a new platform for build, publish and deployment pipelines: enabling parallel execution, dependency tracking, and extensible workflows for building, publishing, and deploying applications.
• Modern CLI: aspire init to Aspirify existing apps, and improved deployment state management that remembers your configuration across runs.
• VS Code extension: Streamlined Aspire development with commands for project creation, integration management, multi-language debugging, and deployment.

Along with the rebranding, Aspire now has a new home at aspire.dev — your central hub for documentation, getting started guides, and community resources.

Requirements:

• .NET 10 SDK or later.

If you have feedback, questions, or want to contribute to Aspire, collaborate with us on GitHub or join us on our new Discord to chat with the team and other community members.

🆙 Upgrade to Aspire 13.0

Cuidado

Aspire 13.0 is a major version release with breaking changes. Please review the Breaking changes section before upgrading.

The easiest way to upgrade to Aspire 13.0 is using the aspire update command:

1. Update the Aspire CLI to the latest version:

   Bash

   curl -sSL https://aspire.dev/install.sh | bash

   PowerShell

   iex "& { $(irm https://aspire.dev/install.ps1) }"

2. Update your Aspire project using the aspire update command:

   Aspire CLI — Update all Aspire packages

   aspire update

   This command will:

   • Update the Aspire.AppHost.Sdk version in your AppHost project.
   • Update all Aspire NuGet packages to version 13.0.
   • Handle dependency resolution automatically.
   • Support both regular projects and Central Package Management (CPM).

3. Update your Aspire templates:

   dotnet new install Aspire.ProjectTemplates

Nota

If you’re upgrading from Aspire 8.x, follow the upgrade guide first to upgrade to 9.x, then upgrade to 13.0.

🧩 AppHost template updates

Aspire 13.0 introduces a simplified AppHost project template structure. The SDK now encapsulates the Aspire.Hosting.AppHost package, resulting in cleaner project files.

Before (9.x):

<Project Sdk="Microsoft.NET.Sdk">

  <Sdk Name="Aspire.AppHost.Sdk" Version="9.5.2" />

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net9.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <UserSecretsId>1bf2ca25-7be4-4963-8782-c53a74e10ad9</UserSecretsId>
  </PropertyGroup>

  <ItemGroup>
    <ProjectReference Include="..\MyApp.ApiService\MyApp.ApiService.csproj" />
    <ProjectReference Include="..\MyApp.Web\MyApp.Web.csproj" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="Aspire.Hosting.AppHost" Version="9.5.2" />
    <PackageReference Include="Aspire.Hosting.Redis" Version="9.5.2" />
  </ItemGroup>

</Project>

After (13.0):

<Project Sdk="Aspire.AppHost.Sdk/13.0.0">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net10.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <UserSecretsId>1bf2ca25-7be4-4963-8782-c53a74e10ad9</UserSecretsId>
  </PropertyGroup>

  <ItemGroup>
    <ProjectReference Include="..\MyApp.ApiService\MyApp.ApiService.csproj" />
    <ProjectReference Include="..\MyApp.Web\MyApp.Web.csproj" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="Aspire.Hosting.Redis" Version="13.0.0" />
  </ItemGroup>

</Project>

Key changes:

• Simplified SDK declaration: The SDK is now specified directly in the <Project> tag with its version: Sdk="Aspire.AppHost.Sdk/13.0.0".
• No explicit Aspire.Hosting.AppHost reference: The SDK now automatically includes this package, reducing boilerplate.
• Cleaner structure: Removed the separate <Sdk Name="..." /> element and the Microsoft.NET.Sdk base SDK.
• Target framework: Updated from net9.0 to net10.0.

The aspire update command automatically handles this migration when upgrading from 9.x to 13.0.

Tip

For an even simpler setup, Aspire 13.0 also supports single-file AppHosts that don’t require a project file at all. Single-file AppHosts are perfect for quick prototypes and learning scenarios.

The same project as a file-based AppHost:

apphost.cs

#:sdk Aspire.AppHost.Sdk@13.0.0
#:package Aspire.Hosting.Redis@13.0.0

var builder = DistributedApplication.CreateBuilder(args);

var cache = builder.AddRedis("cache");
var api = builder.AddProject("apiservice", "../MyApi");
                 .WithReference(cache);

builder.Build().Run();

No project file needed - just a single .cs file with package references declared using #:package directives.

🌐 Aspire as a polyglot platform

Aspire 13.0 marks a transformative shift from a .NET-centric orchestration tool to a truly polyglot application platform. Python and JavaScript are now first-class citizens alongside .NET, with comprehensive support for development, debugging, and deployment workflows.

Python as a first-class citizen

Aspire 13.0 introduces comprehensive Python support, making it effortless to build, debug, and deploy Python applications alongside your other services.

Flexible Python application models

Aspire provides three ways to run Python code, each suited to different use cases:

C# — Flexible Python application models

var builder = DistributedApplication.CreateBuilder(args);

// Run a Python script directly
var etl = builder.AddPythonApp("etl-job", "../etl", "process_data.py");

// Run a Python module (python -m celery)
var worker = builder.AddPythonModule("celery-worker", "../worker", "celery")
    .WithArgs("worker", "-A", "tasks", "--loglevel=info");

// Run an executable from the virtual environment (e.g., gunicorn)
var api = builder.AddPythonExecutable("api", "../api", "gunicorn")
    .WithArgs("app:app", "--bind", "0.0.0.0:8000");

Uvicorn integration for ASGI applications

For Python web applications using ASGI frameworks like FastAPI, Starlette, or Quart, Aspire provides dedicated AddUvicornApp support:

C# — Uvicorn integration

var api = builder.AddUvicornApp("api", "./api", "main:app")
    .WithExternalHttpEndpoints()
    .WithHttpHealthCheck("/health");

The AddUvicornApp method automatically:

• Configures HTTP endpoints.
• Sets up appropriate Uvicorn command-line arguments.
• Supports hot-reload during development.
• Integrates with Aspire’s health check system.

Python package management

Aspire 13.0 provides flexible Python package management with automatic detection.

Automatic package manager detection:

When you add a Python app, Aspire automatically detects and configures package management:

C# — Automatic package detection

// If pyproject.toml or requirements.txt exists → automatically uses pip
// If neither exists → creates a virtual environment (.venv)
var api = builder.AddUvicornApp("api", "./api", "main:app");

In most cases, you don’t need to explicitly configure package management—Aspire detects it automatically.

Using uv (recommended for new projects):

For modern Python projects using uv, explicitly opt-in with WithUv():

C# — Using uv for package management

builder.AddUvicornApp("api", "./api", "main:app")
    .WithUv();  // Use uv for package management

When using WithUv(), Aspire:

• Automatically runs uv sync to install dependencies from pyproject.toml.
• Creates isolated virtual environments per project.
• Leverages uv’s performance benefits (10-100x faster than pip).
• Auto-detects Python version from project configuration.

Explicit pip configuration:

To explicitly configure pip behavior, use WithPip():

C# — Using pip for package management

builder.AddUvicornApp("api", "./api", "main:app")
    .WithPip();  // Explicitly use pip for package management

When using WithPip(), Aspire:

• Automatically installs dependencies from requirements.txt or pyproject.toml (pip supports both).
• Detects virtual environments (.venv) by walking up parent directories.
• Creates a virtual environment if one doesn’t exist.

Configuring virtual environment path:

By default, Aspire uses .venv in the app directory as the virtual environment path. Use WithVirtualEnvironment() to specify a custom path or control automatic creation:

C# — Configuring virtual environment path

// Use a custom venv path
builder.AddPythonApp("api", "./api", "main.py")
    .WithVirtualEnvironment("myenv");

// Use existing venv without auto-creation
builder.AddPythonApp("worker", "./worker", "worker.py")
    .WithVirtualEnvironment(".venv", createIfNotExists: false);

By default, createIfNotExists is true, so Aspire will create the virtual environment if it doesn’t exist. Set it to false to require the virtual environment to already exist.

VS Code debugging support

Python applications can be debugged directly in VS Code with full breakpoint support. Aspire 13.0 automatically enables debugging infrastructure for all Python resources - no additional configuration required. See Visual Studio Code extension for more.

Supported debugging scenarios:

• Python scripts: Debug AddPythonApp with breakpoints and variable inspection.
• Python modules: Debug AddPythonModule with module resolution.
• Flask applications: Debug Flask apps with auto-reload.
• Uvicorn/FastAPI: Debug ASGI applications with async/await support.

Note

Debugging is automatically enabled for Python resources. The Aspire VS Code extension generates VS Code launch configurations automatically.

Automatic Dockerfile generation

Aspire automatically generates production-ready Dockerfiles for Python applications when publishing:

C# — Automatic Dockerfile generation

// With uv (recommended)
builder.AddUvicornApp("api", "./api", "main:app")
    .WithUv();

// Or with pip
builder.AddUvicornApp("api", "./api", "main:app")
    .WithPip();

The generated Dockerfile automatically adapts based on your package manager choice:

• With uv: Uses uv for fast dependency installation from pyproject.toml.
• With pip: Uses pip to install dependencies from requirements.txt.

Both approaches use appropriate Python base images and follow container best practices.

Python version detection

Aspire automatically detects the Python version for Dockerfile generation from multiple sources (in priority order):

1. .python-version file (highest priority).
2. pyproject.toml - requires-python field.
3. Virtual environment - python --version as fallback.

The detected version selects the appropriate Python base image for Docker publishing.

Starter template: Vite + FastAPI

Aspire 13.0 includes a new aspire-py-starter template that demonstrates a full-stack Python application:

Bash — Create Python starter template

aspire new aspire-py-starter

This template includes:

• FastAPI backend: Python ASGI application using Uvicorn.
• Vite + React frontend: Modern JavaScript frontend with TypeScript.
• OpenTelemetry integration: Distributed tracing, logs, and metrics.
• Redis caching (optional): A distributed cache across requests.
• Container files: Frontend static files served by the Python backend.

Build a full-stack polyglot app—Python back end + JavaScript front end—fast. Explore it, customize it, ship it. Create one now and deploy it today!

The React front end communicates with the FastAPI back end via HTTP endpoints, demonstrating seamless integration between the two languages within a single Aspire application. The new template has a modern UX:

JavaScript as a first-class citizen

Aspire 13.0 refactors and expands JavaScript support. In earlier versions, the Aspire.Hosting.NodeJs integration enabled JavaScript applications. In Aspire 13.0, the integration was renamed to Aspire.Hosting.JavaScript and it introduces AddJavaScriptApp as the foundational method for all JavaScript applications.

Unified JavaScript application model

The new AddJavaScriptApp method replaces the older AddNpmApp (removed) and provides a consistent way to add JavaScript applications:

C# — Unified JavaScript application model

var builder = DistributedApplication.CreateBuilder(args);

// Add a JavaScript application - runs "npm run dev" by default
var frontend = builder.AddJavaScriptApp("frontend", "./frontend");

// Use a different package manager
var admin = builder.AddJavaScriptApp("admin", "./admin")
    .WithYarn();

By default, AddJavaScriptApp:

• Automatically detects npm from package.json.
• Runs the “dev” script during local development.
• Runs the “build” script when publishing to create production assets.
• Automatically generates Dockerfiles to build production assets.

Package manager flexibility

Aspire automatically detects and supports multiple JavaScript package managers with intelligent defaults for both development and production scenarios.

Auto-install by default:

Starting in Aspire 13.0, package managers automatically install dependencies by default (install = true). This ensures dependencies are always up-to-date during development and publishing.

Smart defaults for deterministic builds:

When publishing (production mode), Aspire automatically uses deterministic install commands based on the presence of lockfiles:

• npm: Uses npm ci if package-lock.json exists, otherwise npm install.
• yarn:
  • Uses yarn install --immutable if yarn.lock exists and yarn v2+ is detected, otherwise.
  • Uses yarn install --frozen-lockfile if yarn.lock exists, otherwise yarn install.
• pnpm: Uses pnpm install --frozen-lockfile if pnpm-lock.yaml exists, otherwise pnpm install.

This ensures reproducible builds in CI/CD and production environments while remaining flexible during development.

Customizing package managers:

C# — Customizing package managers

// Customize npm with additional flags
var app = builder.AddJavaScriptApp("app", "./app")
    .WithNpm(installCommand: "ci", installArgs: ["--legacy-peer-deps"]);

// Or use different package managers
var yarnApp = builder.AddJavaScriptApp("yarn-app", "./yarn-app")
    .WithYarn(installArgs: ["--immutable"]);

Customizing scripts

You can customize which scripts run during development and build:

C# — Customizing scripts

// Use different script names
var app = builder.AddJavaScriptApp("app", "./app")
    .WithRunScript("start")      // Run "npm run start" during development instead of "dev"
    .WithBuildScript("prod");     // Run "npm run prod" during publish instead of "build"

Vite support

AddViteApp is now a specialization of AddJavaScriptApp with Vite-specific optimizations:

C# — Vite support

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

Vite applications get:

• Automatic port binding configuration.
• Hot module replacement (HMR) support.
• Optimized build scripts for production.
• Automatic Dockerfile generation.

Dynamic Dockerfile generation

JavaScript applications automatically generate Dockerfiles when published, with intelligent defaults based on your package manager:

C# — Dynamic Dockerfile generation

var app = builder.AddJavaScriptApp("app", "./app");

The generated Dockerfile:

• Detects Node.js version from .nvmrc, .node-version, package.json, or .tool-versions.
• Uses multi-stage builds for smaller images.
• Installs dependencies in a separate layer for better caching.
• Runs your build script to create production assets.
• Defaults to node:22-slim if no version is specified.

For information about using JavaScript build artifacts in other containers, see Container files as build artifacts.

Node support

AddNodeApp has now been refactored to align with other language integrations.

C# — Node support

var app = builder.AddNodeApp("frontend", "./frontend", "app.js")
    .WithReference(api);

Node.js applications get:

• Defaults to npm when package.json exists.
• Allows for customizing package manager and build/run scripts.
• Automatic Dockerfile generation with multi-stage builds for smaller images (defaults to node:22-alpine if no version is specified).

Polyglot infrastructure

Beyond language-specific support, Aspire 13.0 introduces infrastructure features that work across all languages.

Polyglot connection properties

Database resources now expose multiple connection string formats automatically, making it easy to connect from any language:

C# — Polyglot connection properties

var postgres = builder.AddPostgres("db").AddDatabase("mydb");

// .NET app uses the "ConnectionStrings" configuration section
var dotnetApi = builder.AddProject<Projects.Api>()
    .WithReference(postgres);

// Python app can use URI format
var pythonWorker = builder.AddPythonModule("worker", "./worker", "worker.main")
    .WithEnvironment("DATABASE_URL", postgres.Resource.UriExpression);

// Java app can use JDBC format
var javaApp = builder.AddExecutable("java-app", "java", "./app", ["-jar", "app.jar"])
    .WithEnvironment("DB_JDBC", postgres.Resource.JdbcConnectionStringExpression);

When you reference a database resource with WithReference, Aspire automatically exposes multiple connection properties as environment variables. For example, a PostgreSQL resource named db exposes:

• DB_URI - PostgreSQL URI format: postgresql://user:pass@host:port/dbname.
• DB_JDBCCONNECTIONSTRING - JDBC format: jdbc:postgresql://host:port/dbname.
• DB_HOST, DB_PORT, DB_USERNAME, DB_PASSWORD, DB_DATABASENAME - Individual properties.

The JDBC connection string does not include credentials for security best practices. Use the separate DB_USERNAME and DB_PASSWORD environment variables to authenticate, or configure your JDBC driver to use these properties.

This pattern works for all supported databases (PostgreSQL, SQL Server, Oracle, MySQL, MongoDB, etc.) with appropriate URI and JDBC formats for each.

Note

These new connection property conventions are available in the built-in Aspire database integrations (PostgreSQL, SQL Server, Oracle, MySQL, MongoDB, etc.). If you have custom or community integrations, they may need to be updated to expose these properties. See the connection properties agent documentation for guidance on implementing these conventions in your own integrations.

Certificate trust across languages

Aspire 13.0 automatically configures ASP.NET Development Certificate trust for Python, Node.js, and containerized applications without any additional configuration:

C# — Certificate trust across languages

// Python applications automatically trust development certificates
var pythonApi = builder.AddUvicornApp("api", "./api", "main:app");

// Node.js applications automatically trust development certificates
var nodeApi = builder.AddJavaScriptApp("frontend", "./frontend");

// Containerized applications automatically trust development certificates
var container = builder.AddContainer("service", "myimage");

Aspire automatically:

• Python: Configures SSL_CERT_FILE and REQUESTS_CA_BUNDLE environment variables.
• Node.js: Configures NODE_EXTRA_CA_CERTS environment variable.
• Containers: Mounts certificate bundles and configures appropriate environment variables.
• All platforms: Generates and manages development certificates without manual intervention.

This enables secure HTTPS communication during local development across all languages and containerized services.

Simplified service URL environment variables

Aspire 13.0 introduces polyglot-friendly environment variables that make service discovery easier for non-.NET applications.

C# — Simplified service URL environment variables

var builder = DistributedApplication.CreateBuilder(args);

var api = builder.AddProject<Projects.Api>("api");

// Python app gets simple environment variables
var pythonApp = builder.AddPythonModule("worker", "./worker", "worker.main")
    .WithReference(api); // Sets API and API_HTTPS env vars

await builder.Build().RunAsync();

Instead of complex service discovery formats, non-.NET apps receive simple environment variables:

• API_HTTP=http://localhost:5000—HTTP endpoint.
• API_HTTPS=https://localhost:5001—HTTPS endpoint.

This feature makes Aspire’s service discovery mechanism accessible to any programming language, not just .NET applications with service discovery libraries.

🛠️ CLI and tooling

aspire init command

The new aspire init command provides a streamlined, interactive experience for initializing Aspire solutions with comprehensive project setup and configuration.

Find out more about the aspire init command in the aspire init documentation.

Bash — Initialize new Aspire solution

# Initialize a new Aspire solution - interactive prompts guide you through setup
aspire init

When you run aspire init, the CLI will:

• Discover existing solutions: Automatically finds and updates solution files in the current directory.
• Create single-file AppHost: If no solution exists, creates a single-file AppHost for quick starts.
• Add projects intelligently: Prompts to add projects to your app host.
• Configure service defaults: Sets up service defaults referencing automatically.
• Setup NuGet.config: Creates package source mappings for Aspire packages.
• Manage template versions: Interactively selects the appropriate template version.

The init command simplifies the initial project setup through an interactive workflow that ensures consistent configuration across team members.

Note

The aspire init command sets up the Aspire project structure and configuration, but does not automatically add resources (databases, caches, message queues, etc.) to your AppHost. You’ll need to manually add resource definitions to your AppHost code using methods like AddPostgres, AddRedis, AddRabbitMQ, etc.

aspire new: Curated starter templates

Aspire 13.0 refocuses aspire new around curated starter templates that demonstrate different application patterns. The command now provides an interactive experience designed to help you get started quickly with ready-to-run examples.

aspire new

When you run the command, you’ll see an interactive menu to select a starter template:

Select a template:

> Blazor & Minimal API starter
  React (Vite) & FastAPI starter
  Empty AppHost

(Type to search)

Available starter templates:

• Blazor & Minimal API starter: Full-stack .NET application with Blazor frontend and ASP.NET Core API.
• React (Vite) & FastAPI starter: Polyglot application demonstrating Python and JavaScript integration.
• Empty AppHost: Minimal single-file AppHost for custom applications.

The starter template collection is designed to be extensible and will grow over time to showcase different architectural patterns and technology combinations. This approach makes it easier to explore Aspire’s capabilities and learn from working examples.

For command reference material, see the aspire new documentation.

Aspire update improvements

The aspire update command has received significant improvements in Aspire 13.0, including the new --self flag to update the CLI itself:

Bash — Aspire update commands

# Update all Aspire packages in the current project
aspire update

# Update the Aspire CLI itself (new in 13.0)
aspire update --self

# Update a specific project
aspire update --project ./src/MyApp.AppHost

New in Aspire 13.0:

• CLI self-update: The --self flag allows you to update the Aspire CLI without reinstalling.
• Improved reliability: Numerous bug fixes for edge cases in dependency resolution.
• Better error handling: Clearer error messages when updates fail.
• Performance improvements: Faster package detection and update operations.

The aspire update command continues to support:

• Central package management (CPM) solutions.
• Diamond dependency resolution.
• Single-file app hosts.
• XML fallback parsing for unresolvable AppHost SDKs.
• Enhanced visual presentation with colorized output.
• Channel awareness (stable, preview, staging).

For detailed command reference, see aspire update.

Visual Studio Code extension

Aspire 13.0 includes a new Aspire VS Code extension which brings Aspire CLI features to VS Code. It provides commands to create and debug projects, add integrations, configure launch settings, and manage deployments directly from the Command Palette.

Note

To use most extension features, the Aspire 13.0 CLI must be installed and available on the user PATH. You can verify this by running aspire --version in a VS Code terminal. For installation steps, see Upgrade to Aspire 13.0.

Key features:

• Debug Python and C# projects inside VS Code: Launch your apphost using the Aspire debugger to launch and debug any C# and Python resources in your app.
• Project creation: Use Aspire: New Aspire project to create new Aspire projects from templates.
• Integration management: Use Aspire: Add an integration to add Aspire integrations to your AppHost.
• Launch configuration: Use Aspire: Configure launch.json to automatically set up a VS Code launch configuration.
• Configuration management: Use Aspire: Manage configuration settings to configure Aspire CLI settings.
• Publish and deployment: Use Aspire: Publish deployment artifacts and Aspire: Deploy app commands (preview).

Getting started:

1. Install the extension from the VS Code Marketplace.
2. Open the Command Palette (Ctrl+Shift+P).
3. Type “Aspire” to see all available commands.
4. Use Aspire: Configure launch.json to set up debugging for your AppHost.

The extension requires the Aspire CLI to be installed and available on your PATH. All commands are grouped under the Aspire category in the Command Palette for easy discovery.

Single-file AppHost support

Aspire 13.0 introduces comprehensive support for single-file app hosts, allowing you to define your entire distributed application in a single .cs file without a project file.

C# — Single-file AppHost

// apphost.cs
#:sdk Aspire.AppHost.Sdk@13.0.0
#:package Aspire.Hosting.PostgreSQL@13.0.0

var builder = DistributedApplication.CreateBuilder(args);

var database = builder.AddPostgres("postgres");

builder.AddProject<Projects.Api>("api")
    .WithReference(database);

await builder.Build().RunAsync();

Single-file app host support includes:

• Template support: Use the aspire-apphost-singlefile template via aspire new.
• Full CLI integration: Works seamlessly with aspire run, aspire deploy, aspire publish, aspire add, aspire update.
• Launch profile support: Full debugging and launch configuration support.

Note

Single-file app hosts require .NET 10.0 SDK or later.

Automatic .NET SDK installation (Preview)

The Aspire CLI includes a preview feature for automatically installing required .NET SDK versions when they’re missing.

Caution

This is a preview feature that is not enabled by default. To use automatic SDK installation, enable it with:

aspire config set features.dotnetSdkInstallationEnabled true

Once enabled, the CLI will automatically install missing SDKs:

# With the feature enabled, the CLI will automatically install the required SDK
aspire run

# Installing .NET SDK 10.0.100...
# ✅ SDK installation complete
# Running app host...

The automatic SDK installation feature provides:

• Cross-platform support: Works on Windows, macOS, and Linux.
• Version detection: Automatically detects required SDK versions.
• Fallback support: Provides alternative installation options if automatic installation fails.

When enabled, this preview feature can improve the onboarding experience for new team members and CI/CD environments.

Non-interactive mode for CI/CD

The --non-interactive flag disables prompts and interactive progress indicators for CI/CD scenarios. The CLI automatically detects common CI environments and enables this mode. You can also set ASPIRE_NON_INTERACTIVE=true or use --non-interactive explicitly.

Note

Not all commands support non-interactive mode. Commands that require user input will fail if the --non-interactive flag is set and required values are not provided through other means.

---

For advanced deployment workflows, see aspire do, which introduces a comprehensive pipeline system for coordinating build, deployment, and publishing operations.

⭐ Major new features

aspire do

Aspire 13.0 introduces aspire do - a comprehensive system for coordinating build, deployment, and publishing operations. This new architecture provides a foundation for orchestrating complex deployment workflows with built-in support for step dependencies, parallel execution, and detailed progress reporting.

The aspire do system replaces the previous publishing infrastructure with a more flexible, extensible model that allows resource-specific deployment logic to be decentralized and composed into larger workflows.

Caution

🧪 Early Preview: The pipeline APIs are in early preview and marked as experimental. See aspire do command reference for more information.

For basic CLI commands and tooling, see CLI and tooling, which covers aspire init, aspire update, and non-interactive mode.

Example: Custom pipeline step

The Aspire AppHost defines a global DistributedApplicationPipeline instance on the DistributedApplicationBuilder that can be used to register steps in the pipeline at the top-level.

C# — Custom pipeline step

var builder = DistributedApplication.CreateBuilder(args);

builder.Pipeline.AddStep("validate", (context) =>
{
    context.Logger.LogInformation("Running validation checks...");
    // Your custom validation logic
    return Task.CompletedTask;
}, requiredBy: WellKnownPipelineSteps.Build);

Steps registered in the pipeline can be run via the CLI:

Bash — Run custom pipeline step

aspire do validate

The pipeline system supports global steps, resource-specific steps, dependency configuration, parallel execution, and built-in logging. Resources can contribute their own steps via WithPipelineStepFactory and control ordering with WithPipelineConfiguration.

Running pipeline steps

Use aspire do to execute pipeline steps. The command automatically resolves dependencies and executes steps in the correct order:

Bash — Running pipeline steps

aspire do deploy                              # Runs all steps necessary to deploy the app
aspire do publish --output-path ./artifacts   # Custom output path
aspire do deploy --environment Production     # Target specific environment
aspire do deploy --log-level debug            # Verbose logging for troubleshooting

Container files as build artifacts

Aspire 13.0 introduces the ability to extract files from one resource’s container and copy them into another resource’s container during the build process. This enables powerful patterns like building a frontend in one container and serving it from a backend in another container.

C# — Container files as build artifacts

var frontend = builder.AddViteApp("frontend", "./frontend");
var api = builder.AddUvicornApp("api", "./api", "main:app");

// Extract files FROM the frontend container and copy TO the 'static' folder
// in the api container
api.PublishWithContainerFiles(frontend, "./static");

How it works:

1. The frontend resource builds inside its container, producing output files.
2. Aspire extracts those files from the frontend container.
3. The files are copied into the api container at ./static.
4. The final api container contains both the API code and the frontend static files.

Example: Serving frontend from backend

The FastAPI app can serve the static files:

Python — Serving front end from back end

from fastapi import FastAPI
from fastapi.staticfiles import StaticFiles

app = FastAPI()

# API endpoints
@app.get("/api/data")
def get_data():
    return {"message": "Hello from API"}

# Serve the frontend static files
app.mount("/", StaticFiles(directory="static", html=True), name="static")

This pattern works with any resource types (C#, Python, JavaScript) and integrates seamlessly with aspire do for dependency tracking, parallel execution, and incremental builds.

Dockerfile builder API (experimental)

Aspire 13.0 introduces an experimental programmatic Dockerfile generation API that allows you to define Dockerfiles using C# code with a composable, type-safe API.

Caution

🧪 Experimental Feature: The Dockerfile Builder API is experimental and may change before general availability.

var app = builder.AddContainer("app", "app")
    .PublishAsDockerFile(publish =>
    {
        publish.WithDockerfileBuilder("/path/to/app", context =>
        {
            var buildStage = context.Builder
                .From("golang:1.23", "builder")
                .WorkDir("/build")
                .Copy(".", "./")
                .Run("go build -o /app/server .");

            context.Builder
                .From("alpine:latest")
                .CopyFrom(buildStage.StageName!, "/app/server", "/app/server")
                .Entrypoint(["/app/server"]);
        });
    });

The API provides multi-stage builds, fluent method chaining (WorkDir, Copy, Run, Env, User, Entrypoint), comments/formatting, and BuildKit features.

Certificate management

Aspire 13.0 introduces certificate management for custom certificate authorities and developer certificate trust:

// Add custom certificate collections
var certs = builder.AddCertificateAuthorityCollection("custom-certs")
    .WithCertificatesFromFile("./certs/my-ca.pem")
    .WithCertificatesFromStore(StoreName.CertificateAuthority, StoreLocation.LocalMachine);

var gateway = builder.AddYarp("gateway")
    .WithCertificateAuthorityCollection(certs)
    .WithDeveloperCertificateTrust(trust: true);

Features include loading from PEM files or certificate stores, flexible trust scoping, customizable container paths, and automatic dev certificate trust configuration.

📦 Integrations

Aspire 13.0 introduces new integration packages that expand platform support.

.NET MAUI integration

Aspire 13.0 introduces a new Aspire.Hosting.Maui package that enables orchestrating .NET MAUI mobile applications alongside your cloud services.

var builder = DistributedApplication.CreateBuilder(args);

var api = builder.AddProject<Projects.Api>("api");

// To easily reach your local API project from the
// emulator/Simulator/physical device, you can use the Dev Tunnels integration
var publicDevTunnel = builder.AddDevTunnel("devtunnel-public")
    .WithAnonymousAccess()
    .WithReference(api.GetEndpoint("https"));

// Add the .NET MAUI project resource
var mauiapp = builder.AddMauiProject("myapp", @"../MyApp/MyApp.csproj");

// Add MAUI app for Windows
mauiapp.AddWindowsDevice()
    .WithReference(weatherApi);

// Add MAUI app for Mac Catalyst
mauiapp.AddMacCatalystDevice()
    .WithReference(weatherApi);

// Add MAUI app for iOS running on the iOS Simulator (starts
// a random one, or uses the currently started one)
mauiapp.AddiOSSimulator()
    .WithOtlpDevTunnel() // Needed to get the OpenTelemetry data to "localhost"
    .WithReference(weatherApi, publicDevTunnel); // Needs a dev tunnel to reach "localhost"

// Add MAUI app for Android running on the emulator with
// default emulator (uses running or default emulator, needs to be started)
mauiapp.AddAndroidEmulator()
    .WithOtlpDevTunnel() // Needed to get the OpenTelemetry data to "localhost"
    .WithReference(weatherApi, publicDevTunnel); // Needs a dev tunnel to reach "localhost"

builder.Build().Run();

MAUI integration features:

• Platform support: Windows, Mac Catalyst, Android, and iOS
• Device registration: Register multiple device instances for testing
• Platform validation: Automatically detects host OS compatibility and marks resources as unsupported when needed
• Full orchestration: MAUI apps participate in service discovery and can reference backend services

This enables a complete mobile + cloud development experience where you can run and debug your mobile app alongside your backend services in a single Aspire project.

📊 Dashboard enhancements

Aspire MCP server

The Dashboard now includes an MCP server that integrates Aspire into your AI development ecosystem. The MCP server enables AI assistants to query resources, access telemetry data, and execute commands directly from your development environment.

Getting started:

1. Run your Aspire app and open the dashboard.
2. Click the MCP button in the top right corner.
3. Follow the instructions to configure your AI assistant (Claude Code, GitHub Copilot CLI, Cursor, VS Code, etc.).

The MCP server uses streamable HTTP with API key authentication for secure access. Configuration requires:

• url: The Aspire MCP endpoint address.
• type: Set to “http” for the streamable-HTTP MCP server.
• x-mcp-api-key: HTTP header for authentication.

Available tools:

• list_resources—Retrieve all resources with state, endpoints, environment variables, and metadata.
• list_console_logs—Access resource console output.
• list_structured_logs—Retrieve telemetry data, optionally filtered by resource.
• list_traces—Access distributed trace information.
• list_trace_structured_logs—View logs associated with specific traces.
• execute_resource_command—Execute commands on resources.

This enables AI assistants to directly interact with your Aspire applications, analyze telemetry in real-time, and provide intelligent insights during development.

Interaction services dynamic inputs and comboboxes

The interaction service just got a major upgrade:

• 💫 Dropdowns can now accept text—in other words, ComboBox inputs. For more information, see interaction service custom choice.
• 🔄 Supports dynamic data loading for cascading dropdowns. For more information, see interaction service dynamic inputs.

You can see an example of the new interaction service features in the dashboard with the Azure provisioning dialog. 🚀

Polyglot language icons

Aspire is going polyglot with strong support for JavaScript ☕ and Python 🐍 apps. The dashboard features new programming language icons for app resources. This includes .NET projects (C#, F#, VB.NET) and JavaScript and Python apps.

Improved accent colors

Resources in the dashboard have accent colors, which is used to color their icon and telemetry. Accent colors are now more FluentUI-ish (saturation++) with custom tweaks for light and dark themes.

The dark blue accent color is no longer almost invisible on a dark background!

Health checks last run time

The dashboard makes it easy to see resource health statuses. New in Aspire 13, the last run time is now displayed next to each resource’s current state. This helps you tell whether an unhealthy resource is still being checked and progressing toward a healthy state.

🖥️ App model enhancements

C# file-based app support

Aspire 13.0 adds first-class support for C# file-based applications, enabling you to add C# apps without full project files to your distributed application.

apphost.cs

#:sdk Aspire.AppHost.Sdk@13.0.0
#:package Aspire.Hosting.Redis@13.0.0

// Type is for evaluation purposes only and is subject to change or
// removal in future updates. Suppress this diagnostic to proceed.
#pragma warning disable ASPIRECSHARPAPPS001

var builder = DistributedApplication.CreateBuilder(args);

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

builder.AddCSharpApp("worker", "../worker/Program.cs")
    .WithReference(cache);

builder.Build().Run();

This works seamlessly with .NET 10 SDK’s file-based application support. The C# file-based app can use service discovery, access referenced resources, and be debugged in VS Code just like regular projects.

Network identifiers

Aspire 13.0 introduces NetworkIdentifier for better network context awareness in endpoint resolution.

var builder = DistributedApplication.CreateBuilder(args);

var api = builder.AddProject<Projects.Api>("api");

// Get endpoint with specific network context
var localhostEndpoint = api.GetEndpoint("http", KnownNetworkIdentifiers.LocalhostNetwork);
var containerEndpoint = api.GetEndpoint("http", KnownNetworkIdentifiers.DefaultAspireContainerNetwork);

await builder.Build().RunAsync();

Network identifier features:

• Context-aware endpoint resolution: Resolve endpoints based on the network context (host, container network, etc.)
• Known network identifiers: Predefined identifiers for common scenarios (LocalhostNetwork, DefaultAspireContainerNetwork, PublicInternet)
• AllocatedEndpoint changes: Endpoints now include their NetworkID instead of a container host address
• Better container networking: Improved support for container-to-container communication scenarios

Interaction service dynamic inputs

The interaction service has been improved with support for dynamic inputs. This feature allows inputs to load options based on other input values, enabling cascading dropdowns and dependent parameter prompting.

Note

This is an experimental feature marked with [Experimental("ASPIREINTERACTION001")].

var inputs = new List<InteractionInput>
{
    // First input - static options
    new InteractionInput
    {
        Name = "DatabaseType",
        InputType = InputType.Choice,
        Label = "Database Type",
        Required = true,
        Options =
        [
            KeyValuePair.Create("postgres", "PostgreSQL"),
            KeyValuePair.Create("mysql", "MySQL"),
            KeyValuePair.Create("sqlserver", "SQL Server")
        ]
    },

    // Second input - loads dynamically based on DatabaseType
    new InteractionInput
    {
        Name = "DatabaseVersion",
        InputType = InputType.Choice,
        Label = "Database Version",
        Required = true,
        DynamicLoading = new InputLoadOptions
        {
            LoadCallback = async (context) =>
            {
                var dbType = context.AllInputs["DatabaseType"].Value;
                context.Input.Options = await GetAvailableVersionsAsync(dbType);
            },
            DependsOnInputs = ["DatabaseType"]
        }
    }
};

Features include callback-based loading (LoadCallback), dependency tracking (DependsOnInputs), access to other input values (context.AllInputs), and async support for loading from APIs or databases.

Interaction service custom choices

Choice inputs can be configured to accept custom choices by setting AllowCustomChoice to true. In the dashboard, these inputs are displayed as a combobox.

var input = new InteractionInput
{
    Name = "AllowCustomInput",
    Label = "Favorite food?",
    InputType = InputType.Choice,
    Options = [KeyValuePair.Create("pizza", "Pizza"), KeyValuePair.reate("burger", "Burger")],
    AllowCustomChoice = true
};

var result = await interactionService.PromptInputAsync("What is your favorite food?", "Select your favorite food.", input);

Reference and connection improvements

Named references

Reference resources with explicit names to control the environment variable prefix:

var builder = DistributedApplication.CreateBuilder(args);

var primaryDb = builder.AddPostgres("postgres-primary")
    .AddDatabase("customers");

var replicaDb = builder.AddPostgres("postgres-replica")
    .AddDatabase("customers");

var api = builder.AddProject<Projects.Api>("api")
    .WithReference(primaryDb, "primary")
    .WithReference(replicaDb, "replica");

Environment variables injected into api:

# From primaryDb with "primary" name
ConnectionStrings__primary=Host=postgres-primary;...

# From replicaDb with "replica" name
ConnectionStrings__replica=Host=postgres-replica;...

This allows the application to distinguish between multiple database connections using the custom names.

Connection properties

Access individual connection string components to build custom connection strings or configuration:

var builder = DistributedApplication.CreateBuilder(args);

var postgres = builder.AddPostgres("postgres").AddDatabase("mydb");
var redis = builder.AddRedis("cache");

var worker = builder.AddProject<Projects.Worker>("worker")
    .WithEnvironment("DB_HOST", postgres.Resource.GetConnectionProperty("Host"))
    .WithEnvironment("DB_PORT", postgres.Resource.GetConnectionProperty("Port"))
    .WithEnvironment("DB_NAME", postgres.Resource.DatabaseName)
    .WithEnvironment("CACHE_HOST", redis.Resource.GetConnectionProperty("Host"))
    .WithEnvironment("CACHE_PORT", redis.Resource.GetConnectionProperty("Port"));

Environment variables injected into worker:

DB_HOST=postgres
DB_PORT=5432
DB_NAME=mydb
CACHE_HOST=cache
CACHE_PORT=6379

This is useful when your application needs individual connection components rather than a full connection string, or when building connection strings in formats Aspire doesn’t provide natively.

Endpoint reference enhancements

Control how service URLs are resolved and injected with network-aware endpoint references:

var builder = DistributedApplication.CreateBuilder(args);

var api = builder.AddProject<Projects.Api>("api")
    .WithExternalHttpEndpoints();

var frontend = builder.AddJavaScriptApp("frontend", "./frontend")
    .WithEnvironment("API_URL", api.GetEndpoint("https"));

Environment variables injected into frontend:

# Default behavior - uses the external endpoint URL
API_URL=https://localhost:7123

For advanced scenarios, you can specify the network context:

var worker = builder.AddProject<Projects.Worker>("worker")
    .WithEnvironment("API_URL",
        api.GetEndpoint("http",
            KnownNetworkIdentifiers.DefaultAspireContainerNetwork));

Environment variables injected into worker:

# Container network context - uses internal container address
API_URL=http://api:8080

This enables proper service-to-service communication whether the consumer is running on the host or in a container.

Other app model improvements

Compute environment support (graduated from experimental):

• WithComputeEnvironment API is now stable (no longer marked as experimental)
• Deploy resources to specific compute environments without experimental warnings

Resource exclusion from MCP:

• ExcludeFromMcp extension to exclude specific resources from Model Context Protocol exposure
• Control which resources are visible to AI assistants and MCP clients

Reference environment injection control:

• WithReferenceEnvironment to control how environment variables are injected from references
• ReferenceEnvironmentInjectionFlags for fine-grained control over environment variable behavior

Helper methods:

• TryCreateResourceBuilder for safely attempting resource builder creation with failure handling
• Returns false instead of throwing when resource builder creation fails

🚀 Deployment improvements

Deployment pipeline reimplementation

Aspire 13.0 completely reimplements the deployment workflow on top of aspire do. This architectural change transforms deployment from a monolithic operation into a composable set of discrete, parallelizable steps.

The new deployment pipeline automatically parallelizes independent operations, dramatically reducing deployment time. Steps like prerequisites, builds, and provisioning run concurrently when dependencies allow.

Granular step control:

Execute individual deployment phases using aspire do:

aspire do build                           # Build all containers
aspire deploy                             # Complete deployment
aspire do deploy --log-level debug        # Deploy with verbose logging

This enables incremental deployments, debugging specific steps, and CI/CD pipeline splitting. Use --log-level debug for detailed troubleshooting output.

Pipeline diagnostics:

Use aspire do diagnostics to understand your pipeline graph, view execution order with parallelization indicators, see step dependencies and resources, simulate “what if” scenarios, and detect configuration issues like orphaned steps or circular dependencies.

Benefits:

The pipeline-based deployment provides dependency tracking, real-time progress reporting, failure isolation, selective execution, extensibility, and built-in diagnostics.

For more details, see aspire do.

Deployment state management

Aspire 13.0 introduces deployment state management that automatically persists deployment information locally across runs. When you deploy to Azure, Aspire now remembers your choices and deployment state between sessions.

What persists locally:

• Azure configuration: Subscription, resource group, location, and tenant selections
• Parameter values: Input values from previous deployments
• Deployed resources: Track what’s been deployed and where

User experience:

# First deployment - you're prompted for configuration, assumes "Production" environment
aspire deploy
# Select Azure subscription, resource group, location, tenant...

# Subsequent deployments - no prompts, uses saved state
aspire deploy
# Uses previous selections automatically

# First deployment to a different environment -- prompted again
aspire deploy --environment staging

This eliminates repetitive prompts and makes iterative deployments faster. Your deployment configuration is stored locally (not in source control), so each developer can have their own Azure configuration without conflicts.

Example workflow:

1. First time: Select subscription “My Subscription”, resource group “my-rg”, location “eastus”
2. Deploy completes, state saved locally
3. Make code changes
4. Run aspire deploy again - automatically uses “My Subscription”, “my-rg”, “eastus”
5. No need to re-enter configuration

Storage location:

The state is stored in your local user profile at:

• Windows: %USERPROFILE%\.aspire\deployments\<project-hash>\<environment>.json
• macOS/Linux: $HOME/.aspire/deployments/<project-hash>/<environment>.json

The <project-hash> is a SHA256 hash of your AppHost project path, allowing different projects to maintain separate state. The <environment> corresponds to the deployment environment (e.g., production, development).

This location is excluded from source control by design, so each developer can have their own Azure configuration without conflicts.

Resetting deployment state:

If you need to reset your deployment state (for example, to change subscriptions or start fresh), use the --clear-cache flag:

aspire deploy --clear-cache
# Clears saved state and prompts for configuration again

This removes all saved deployment state, including Azure configuration, parameter values, and deployment context. The next deployment will prompt you for all configuration values as if it were the first deployment.

☁️ Azure

Azure tenant selection

Aspire 13.0 introduces interactive tenant selection during Azure provisioning, fixing issues with multi-tenant scenarios (work and personal accounts).

When provisioning Azure resources, if multiple tenants are available, the CLI will prompt you to select the appropriate tenant. The tenant selection is stored alongside your subscription, location, and resource group choices for consistent deployments.

aspire deploy

# If you have multiple tenants, you'll be prompted:
# Select Azure tenant:
#   > work@company.com (Default Directory)
#     personal@outlook.com (Personal Account)

Azure App Service enhancements

Aspire 13.0 brings significant improvements to Azure App Service deployment, making it easier to deploy and monitor your applications in production.

Aspire dashboard in App Service

The Aspire Dashboard is now included by default when deploying to Azure App Service, giving you visibility into your deployed applications:

builder.AddAzureAppServiceEnvironment("env");
// Dashboard is included by default at https://[prefix]-aspiredashboard-[unique string].azurewebsites.net

The deployed dashboard provides the same experience as local development: view logs, traces, metrics, and application topology for your production environment.

To disable the dashboard:

builder.AddAzureAppServiceEnvironment("env")
    .WithDashboard(enable: false);

Application Insights integration

Enable Azure Application Insights for comprehensive monitoring and telemetry:

builder.AddAzureAppServiceEnvironment("env")
    .WithAzureApplicationInsights();

When enabled, Aspire automatically:

• Creates a Log Analytics workspace.
• Creates an Application Insights resource.
• Configures all App Service Web Apps with the connection string.
• Injects APPLICATIONINSIGHTS_CONNECTION_STRING into your applications.

You can also reference an existing Application Insights resource:

var insights = builder.AddAzureApplicationInsights("insights");

builder.AddAzureAppServiceEnvironment("env")
    .WithAzureApplicationInsights(insights);

⚠️ Breaking changes

Package renames

Aspire.Hosting.NodeJs → Aspire.Hosting.JavaScript

The Aspire.Hosting.NodeJs package has been renamed to Aspire.Hosting.JavaScript to better reflect its broader support for JavaScript applications (Node.js, Vite, etc.).

Update your package references:

<!-- Before (9.x) -->
<PackageReference Include="Aspire.Hosting.NodeJs" Version="9.x.x" />

<!-- After (13.0) -->
<PackageReference Include="Aspire.Hosting.JavaScript" Version="13.0.0" />

Or use the CLI:

# Before (9.x)
aspire add nodejs

# After (13.0)
aspire add javaScript

Removed APIs

The following APIs have been removed in Aspire 13.0:

Publishing infrastructure (replaced by aspire do):

• PublishingContext and PublishingCallbackAnnotation
• DeployingContext and DeployingCallbackAnnotation
• WithPublishingCallback extension method
• IDistributedApplicationPublisher interface
• IPublishingActivityReporter, IPublishingStep, IPublishingTask interfaces
• NullPublishingActivityReporter class
• PublishingExtensions class (all extension methods)
• PublishingOptions class
• CompletionState enum

Debugging APIs (replaced with new flexible API):

• Old WithDebugSupport overload with debugAdapterId and requiredExtensionId parameters
• SupportsDebuggingAnnotation (replaced with new debug support annotation)

Diagnostic codes:

• ASPIRECOMPUTE001 diagnostics (removed - API graduated from experimental)
• ASPIREPUBLISHERS001 (renamed to ASPIREPIPELINES001-003)

CLI commands:

• --watch flag removed from aspire run (replaced by features.defaultWatchEnabled feature flag)

Obsolete APIs

The following APIs are marked as obsolete in Aspire 13.0 and will be removed in a future release:

Lifecycle hooks:

• IDistributedApplicationLifecycleHook interface - Use IDistributedApplicationEventingSubscriber instead

Lifecycle hook extension methods (use eventing subscriber extensions instead):

• AddLifecycleHook<T>() - Use AddEventingSubscriber<T>() instead
• AddLifecycleHook<T>(Func<IServiceProvider, T>) - Use AddEventingSubscriber<T>(Func<IServiceProvider, T>) instead
• TryAddLifecycleHook<T>() - Use TryAddEventingSubscriber<T>() instead
• TryAddLifecycleHook<T>(Func<IServiceProvider, T>) - Use TryAddEventingSubscriber<T>(Func<IServiceProvider, T>) instead

Publishing interfaces (use aspire do instead):

• IDistributedApplicationPublisher - Use PipelineStep instead
• PublishingOptions - Use PipelineOptions instead

Node.js/JavaScript APIs (use new JavaScript hosting instead):

• AddNpmApp() - Use AddJavaScriptApp() instead for general npm-based apps, or AddViteApp() for Vite projects

While the obsoleted APIs still work in 13.0, they will be removed in the next major version. Update your code to use the recommended replacements.

Changed signatures

AllocatedEndpoint constructor:

// Before (9.x)
var endpoint = new AllocatedEndpoint("http", 8080, containerHostAddress: "localhost");

// After (13.0)
var endpoint = new AllocatedEndpoint("http", 8080, networkIdentifier: NetworkIdentifier.Host);

ParameterProcessor constructor:

// Before (9.x)
var processor = new ParameterProcessor(distributedApplicationOptions);

// After (13.0)
var processor = new ParameterProcessor(deploymentStateManager);

InteractionInput property changes:

• MaxLength: Changed from settable to init-only.
• Options: Changed from init-only to settable.
• Placeholder: Changed from settable to init-only.

WithReference for IResourceWithServiceDiscovery:

• Added new overload with name parameter for named references.
• Existing overload still available for compatibility.

ProcessArgumentValuesAsync and ProcessEnvironmentVariableValuesAsync:

// Before (9.x)
await resource.ProcessArgumentValuesAsync(
    executionContext, processValue, logger,
    containerHostName: "localhost", cancellationToken);

// After (13.0)
await resource.ProcessArgumentValuesAsync(
    executionContext, processValue, logger, cancellationToken);

The containerHostName parameter has been removed. Network context is now handled through NetworkIdentifier.

EndpointReference.GetValueAsync behavior change:

// Before (9.x) - would throw immediately if not allocated
var value = await endpointRef.GetValueAsync(cancellationToken);

// After (13.0) - waits for allocation, check IsAllocated if you need immediate failure
if (!endpointRef.IsAllocated)
{
    throw new InvalidOperationException("Endpoint not allocated");
}
var value = await endpointRef.GetValueAsync(cancellationToken);

Major architectural changes

Universal container-to-host communication

Aspire 13.0 introduces a major architectural change to enable universal container-to-host communication, independent of container orchestrator support.

What changed:

• Leverages DCP’s container tunnel capability for container-to-host connectivity.
• EndpointReference resolution is now context-aware (uses NetworkIdentifier).
• Endpoint references are tracked by their EndpointAnnotation.
• AllocatedEndpoint constructor signature changed.

Impact:

• Enables containers to communicate with host-based services reliably across all deployment scenarios.
• Code that directly constructs AllocatedEndpoint objects will need updates.
• Extension methods that process endpoint references may need Network Identifier context.

Migration:

The universal container-to-host communication is currently an experimental feature and needs to be enabled via environment variable. Set ASPIRE_ENABLE_CONTAINER_TUNNEL to true to opt in.

Most applications won’t need changes as endpoint resolution happens automatically. However, if you have custom code that creates or processes AllocatedEndpoint objects, you will need to use the new constructor:

// Before (9.x)
var endpoint = new AllocatedEndpoint("http", 8080, containerHostAddress: "localhost");

// After (13.0)
var endpoint = new AllocatedEndpoint("http", 8080, networkIdentifier: NetworkIdentifier.Host);

This change fixes long-standing issues with container-to-host communication (issue #6547).

Refactored AddNodeApp API

The AddNodeApp API has been refactored with breaking changes to how Node.js applications are configured.

Signature changes:

// Before (9.x) - absolute scriptPath with optional workingDirectory
builder.AddNodeApp(
    name: "frontend",
    scriptPath: "/absolute/path/to/app.js",
    workingDirectory: "/absolute/path/to",
    args: ["--port", "3000"]);

// After (13.0) - appDirectory with relative scriptPath
builder.AddNodeApp(
    name: "frontend",
    appDirectory: "../frontend",
    scriptPath: "app.js");

Behavioral changes:

1. Automatic npm integration: If package.json exists in appDirectory, npm is automatically configured with auto-install enabled
2. Automatic Dockerfile generation: Includes Docker publishing support with multi-stage builds by default
3. Package manager flexibility: Use WithNpm(), WithYarn(), or WithPnpm() with WithRunScript() to execute package.json scripts

Migration:

// Before (9.x)
var app = builder.AddNodeApp("frontend", "../frontend/server.js", "../frontend");

// After (13.0)
var app = builder.AddNodeApp("frontend", "../frontend", "server.js");

// Or use package.json script
var app = builder.AddNodeApp("frontend", "../frontend", "server.js")
    .WithNpm()
    .WithRunScript("dev");

Migration guide

Migrating from publishing callbacks to pipeline steps

Before (9.x):

var api = builder.AddProject<Projects.Api>("api")
    .WithPublishingCallback(async (context, cancellationToken) =>
    {
        await CustomDeployAsync(context, cancellationToken);
    });

After (13.0):

var api = builder.AddProject<Projects.Api>("api")
    .WithPipelineStepFactory(context =>
    {
        return new PipelineStep()
        {
            Name = "CustomDeployStep",
            Action = CustomDeployAsync,
            RequiredBySteps = [WellKnownPipelineSteps.Publish]
        };
    });

For more details, see Deployment pipeline documentation.

Migrating from lifecycle hooks to events

Before (9.x):

public class MyLifecycleHook : IDistributedApplicationLifecycleHook
{
    public async Task BeforeStartAsync(
        DistributedApplicationModel model,
        CancellationToken cancellationToken)
    {
        // Logic before start
    }
}

builder.Services.TryAddLifecycleHook<MyLifecycleHook>();

After (13.0):

public class MyEventSubscriber : IDistributedApplicationEventingSubscriber
{
    public Task SubscribeAsync(
        IDistributedApplicationEventing eventing,
        DistributedApplicationExecutionContext executionContext,
        CancellationToken cancellationToken)
    {
        eventing.Subscribe<BeforeStartEvent>((@event, ct) =>
        {
            // Access model and services via event
            var model = @event.Model;
            var services = @event.Services;

            // Logic before start

            return Task.CompletedTask;
        });

        return Task.CompletedTask;
    }
}

builder.Services.TryAddEventingSubscriber<MyEventSubscriber>();

Experimental features

The following features are marked as [Experimental] and may change in future releases:

• Dockerfile builder API: WithDockerfileBuilder, AddDockerfileBuilder, WithDockerfileBaseImage.
• C# file-based app support: AddCSharpApp.
• Dynamic inputs: InputLoadOptions, dynamic input loading.
• Pipeline features: IDistributedApplicationPipeline and related APIs.

To use experimental features, you must enable them explicitly and acknowledge they may change:

#pragma warning disable ASPIREXXX // Experimental feature
var app = builder.AddCSharpApp("myapp", "./app.cs");
#pragma warning restore ASPIREXXX

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Feedback and contributions: We’d love to hear about your experience with Aspire 13.0! Share feedback on GitHub or join the conversation on Discord.