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.

References

1. Researching Aspire Documentation

The Aspire team ships an MCP server that provides documentation tools directly inside your AI assistant. See MCP Server (opens in a new tab) 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:

These tools were added in PR #14028 (opens in a new tab). 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/ (opens in a new tab)

Aspire CLI 13.1 (integration tools only)

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

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".

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

2. Prerequisites & Install

# 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

3. Project Templates

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 (opens in a new tab).

5. Core Concepts (Summary)

6. CLI Quick Reference

Valid commands in Aspire CLI 13.1:

Full command reference with flags: CLI Reference (opens in a new tab).

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()

8. Key URLs