Msbuild Server

MSBuild Server for CLI Caching

When to Use

• Small incremental builds from CLI (dotnet build) are slower than expected
• Developers notice that VS builds are faster than CLI builds for the same project
• CI agents run many sequential builds of the same repo

How It Works

By default, each dotnet build invocation starts a fresh MSBuild process. The MSBuild Server keeps a long-lived process that caches evaluation results, resolved assemblies, and other state across builds — similar to how Visual Studio reuses its MSBuild nodes.

Setup

Set the environment variable:

# Bash / CI
export MSBUILDUSESERVER=1

# PowerShell
$env:MSBUILDUSESERVER = "1"

# Windows (persistent)
setx MSBUILDUSESERVER 1

Expected Impact

• First build: no change (server starts cold)
• Subsequent incremental builds: faster due to cached evaluation, resolved references, and warm JIT
• Most noticeable in repos with many projects or complex Directory.Build.props chains

Limitations

• The server process persists in the background — uses some memory
• If builds behave unexpectedly, try dotnet build-server shutdown to reset
• Not all MSBuild features are compatible with server mode