Aspire

Aspire — Polyglot Distributed-App Orchestration

Aspire is a code-first, polyglot toolchain for building observable, production-ready distributed applications. It orchestrates containers, executables, and cloud resources from a single AppHost project — regardless of whether the workloads are C#, Python, JavaScript/TypeScript, Go, Java, Rust, Bun, Deno, or PowerShell.

Mental model: The AppHost is a conductor — it doesn't play the instruments, it tells every service when to start, how to find each other, and watches for problems.

Detailed reference material lives in the references/ folder — load on demand.

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References

Reference	When to load
CLI Reference	Command flags, options, or detailed usage
MCP Server	Setting up MCP for AI assistants, available tools
Integrations Catalog	Discovering integrations via MCP tools, wiring patterns
Polyglot APIs	Method signatures, chaining options, language-specific patterns
Architecture	DCP internals, resource model, service discovery, networking, telemetry
Dashboard	Dashboard features, standalone mode, GenAI Visualizer
Deployment	Docker, Kubernetes, Azure Container Apps, App Service
Testing	Integration tests against the AppHost
Troubleshooting	Diagnostic codes, common errors, and fixes

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1. Researching Aspire Documentation

The Aspire team ships an MCP server that provides documentation tools directly inside your AI assistant. See MCP Server for setup details.

Aspire CLI 13.2+ (recommended — has built-in docs search)

If running Aspire CLI 13.2 or later (aspire --version), the MCP server includes docs search tools:

Tool	Description
list_docs	Lists all available documentation from aspire.dev
search_docs	Performs weighted lexical search across indexed documentation
get_doc	Retrieves a specific document by its slug

These tools were added in PR #14028. To update: aspire update --self --channel daily.

For more on this approach, see David Pine's post: https://davidpine.dev/posts/aspire-docs-mcp-tools/

Aspire CLI 13.1 (integration tools only)

On 13.1, the MCP server provides integration lookup but not docs search:

Tool	Description
list_integrations	Lists available Aspire hosting integrations
get_integration_docs	Gets documentation for a specific integration package

For general docs queries on 13.1, use Context7 as your primary source (see below).

Fallback: Context7

Use Context7 (mcp_context7) when the Aspire MCP docs tools are unavailable (13.1) or the MCP server isn't running:

Step 1 — Resolve the library ID (one-time per session):

Call mcp_context7_resolve-library-id with libraryName: ".NET Aspire".

Rank	Library ID	Use when
1	/microsoft/aspire.dev	Primary source. Guides, integrations, CLI reference, deployment.
2	/dotnet/aspire	API internals, source-level implementation details.
3	/communitytoolkit/aspire	Non-Microsoft polyglot integrations (Go, Java, Node.js, Ollama).

Step 2 — Query docs:

libraryId: "/microsoft/aspire.dev", query: "Python integration AddPythonApp service discovery"
libraryId: "/communitytoolkit/aspire", query: "Golang Java Node.js community integrations"

Fallback: GitHub search (when Context7 is also unavailable)

Search the official docs repo on GitHub:

• Docs repo: microsoft/aspire.dev — path: src/frontend/src/content/docs/
• Source repo: dotnet/aspire
• Samples repo: dotnet/aspire-samples
• Community integrations: CommunityToolkit/Aspire

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2. Prerequisites & Install

Requirement	Details
.NET SDK	10.0+ (required even for non-.NET workloads — the AppHost is .NET)
Container runtime	Docker Desktop, Podman, or Rancher Desktop
IDE (optional)	VS Code + C# Dev Kit, Visual Studio 2022, JetBrains Rider

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

# Windows PowerShell
irm https://aspire.dev/install.ps1 | iex

# Verify
aspire --version

# Install templates
dotnet new install Aspire.ProjectTemplates

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3. Project Templates

Template	Command	Description
aspire-starter	aspire new aspire-starter	ASP.NET Core/Blazor starter + AppHost + tests
aspire-ts-cs-starter	aspire new aspire-ts-cs-starter	ASP.NET Core/React starter + AppHost
aspire-py-starter	aspire new aspire-py-starter	FastAPI/React starter + AppHost
aspire-apphost-singlefile	aspire new aspire-apphost-singlefile	Empty single-file AppHost

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4. AppHost Quick Start (Polyglot)

The AppHost orchestrates all services. Non-.NET workloads run as containers or executables.

var builder = DistributedApplication.CreateBuilder(args);

// Infrastructure
var redis = builder.AddRedis("cache");
var postgres = builder.AddPostgres("pg").AddDatabase("catalog");

// .NET API
var api = builder.AddProject<Projects.CatalogApi>("api")
    .WithReference(postgres).WithReference(redis);

// Python ML service
var ml = builder.AddPythonApp("ml-service", "../ml-service", "main.py")
    .WithHttpEndpoint(targetPort: 8000).WithReference(redis);

// React frontend (Vite)
var web = builder.AddViteApp("web", "../frontend")
    .WithHttpEndpoint(targetPort: 5173).WithReference(api);

// Go worker
var worker = builder.AddGolangApp("worker", "../go-worker")
    .WithReference(redis);

builder.Build().Run();

For complete API signatures, see Polyglot APIs.

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5. Core Concepts (Summary)

Concept	Key point
Run vs Publish	aspire run = local dev (DCP engine). aspire publish = generate deployment manifests.
Service discovery	Automatic via env vars: ConnectionStrings__<name>, services__<name>__http__0
Resource lifecycle	DAG ordering — dependencies start first. .WaitFor() gates on health checks.
Resource types	ProjectResource, ContainerResource, ExecutableResource, ParameterResource
Integrations	144+ across 13 categories. Hosting package (AppHost) + Client package (service).
Dashboard	Real-time logs, traces, metrics, GenAI visualizer. Runs automatically with aspire run.
MCP Server	AI assistants can query running apps and search docs via CLI (STDIO).
Testing	Aspire.Hosting.Testing — spin up full AppHost in xUnit/MSTest/NUnit.
Deployment	Docker, Kubernetes, Azure Container Apps, Azure App Service.

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6. CLI Quick Reference

Valid commands in Aspire CLI 13.1:

Command	Description	Status
aspire new <template>	Create from template	Stable
aspire init	Initialize in existing project	Stable
aspire run	Start all resources locally	Stable
aspire add <integration>	Add an integration	Stable
aspire publish	Generate deployment manifests	Preview
aspire config	Manage configuration settings	Stable
aspire cache	Manage disk cache	Stable
aspire deploy	Deploy to defined targets	Preview
aspire do <step>	Execute a pipeline step	Preview
aspire update	Update integrations (or --self for CLI)	Preview
aspire mcp init	Configure MCP for AI assistants	Stable
aspire mcp start	Start the MCP server	Stable

Full command reference with flags: CLI Reference.

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7. Common Patterns

Adding a new service

1. Create your service directory (any language)
2. Add to AppHost: Add*App() or AddProject<T>()
3. Wire dependencies: .WithReference()
4. Gate on health: .WaitFor() if needed
5. Run: aspire run

Migrating from Docker Compose

1. aspire new aspire-apphost-singlefile (empty AppHost)
2. Replace each docker-compose service with an Aspire resource
3. depends_on → .WithReference() + .WaitFor()
4. ports → .WithHttpEndpoint()
5. environment → .WithEnvironment() or .WithReference()

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8. Key URLs

Resource	URL
Documentation	https://aspire.dev
Runtime repo	https://github.com/dotnet/aspire
Docs repo	https://github.com/microsoft/aspire.dev
Samples	https://github.com/dotnet/aspire-samples
Community Toolkit	https://github.com/CommunityToolkit/Aspire
Dashboard image	mcr.microsoft.com/dotnet/aspire-dashboard
Discord	https://aka.ms/aspire/discord
Reddit	https://www.reddit.com/r/aspiredotdev/