nuget-version-check

name: nuget-version-check description: Methods for checking latest NuGet package versions before adding dependencies to .NET projects. Use when adding new NuGet packages, updating existing packages, or verifying package versions are current. Covers NuGet API queries, dotnet CLI commands, and version selection best practices. Use this skill before running dotnet add package or manually editing PackageReference entries in .csproj files or when user asks to verify package versions

NuGet Version Check

Overview

Always verify the latest package version before adding NuGet dependencies. Outdated versions miss security patches, bug fixes, and features. This guide covers three methods for checking versions, ordered by reliability.

Method 1: NuGet API (Recommended)

Query the NuGet v3 API directly using WebFetch. This is the most reliable method.

API Endpoint

https://api.nuget.org/v3-flatcontainer/{package-id-lowercase}/index.json

Important: Package ID must be lowercase in the URL.

Example

Check Newtonsoft.Json version:

WebFetch URL: https://api.nuget.org/v3-flatcontainer/newtonsoft.json/index.json
Prompt: "What is the latest stable version (no prerelease suffixes)?"

Response contains a versions array in chronological order. The last entry without a prerelease suffix (like -preview, -beta, -rc) is the latest stable version.

Common Package URLs

Constructing URLs

For any package, construct the URL:

1. Take the package ID (e.g., Microsoft.Extensions.Logging)
2. Convert to lowercase (e.g., microsoft.extensions.logging)
3. Insert into template: https://api.nuget.org/v3-flatcontainer/microsoft.extensions.logging/index.json

Method 2: dotnet CLI

Use the dotnet package search command for quick lookups.

Basic Search

dotnet package search Newtonsoft.Json --take 1

Shows the latest version on nuget.org.

Include Prerelease

dotnet package search Microsoft.Extensions.Hosting --prerelease --take 5

Shows prerelease versions alongside stable releases.

Search with Source

dotnet package search Serilog --source https://api.nuget.org/v3/index.json --take 1

Explicitly targets nuget.org (useful if custom feeds are configured).

Method 3: WebFetch nuget.org Website

Fetch the package page directly as a fallback.

WebFetch URL: https://www.nuget.org/packages/Newtonsoft.Json
Prompt: "What is the latest stable version of this package?"

Less reliable than the API due to HTML parsing, but works when the API has issues.

Version Selection Guidelines

Prefer Stable Versions

Avoid prerelease suffixes unless specifically needed:

• -preview - Early development, API may change
• -beta - Feature complete but not production-tested
• -alpha - Experimental, unstable
• -rc - Release candidate, nearly stable

Check Framework Compatibility

Before adding a package, verify it supports your target framework:

dotnet package search PackageName --take 1 --format detailed

Or check the package page for supported frameworks.

Consider Major Version Changes

Major version bumps (e.g., 2.x to 3.x) often have breaking changes. Review:

• Release notes/changelog
• Migration guides
• API compatibility

Microsoft Package Versioning

Microsoft.Extensions.* and Microsoft.AspNetCore.* packages follow .NET versioning:

• .NET 6 projects: Use 6.x.x versions
• .NET 7 projects: Use 7.x.x versions
• .NET 8 projects: Use 8.x.x versions

Match the major version to your target framework.

Workflow Example

Adding a New Package

1. Check latest version:

   WebFetch: https://api.nuget.org/v3-flatcontainer/mediatr/index.json
   

2. Identify latest stable (last version without prerelease suffix)

3. Add to project:

   dotnet add package MediatR --version 12.2.0
   

4. Or edit .csproj directly:

   <PackageReference Include="MediatR" Version="12.2.0" />
   

Updating Existing Packages

1. List outdated packages:

   dotnet list package --outdated
   

2. Check latest version for each outdated package using Method 1 or 2

3. Update specific package:

   dotnet add package PackageName --version X.Y.Z
   

Package Metadata API

For detailed package information (dependencies, description, license):

https://api.nuget.org/v3/registration5-gz-semver2/{package-id-lowercase}/index.json

This returns comprehensive metadata including all versions and their dependencies.