These docs are for v4. Click to read the latest docs for v2024.2.

Using SLAB

The Semantic Logging Application Block (SLAB) from Microsoft's Patterns & Practices team is an alternative structured logger that can write to Seq.


SLAB has been discontinued

The Microsoft team behind Semantic Logging have announced that the project will no longer be actively developed.

While Seq will continue to support SLAB clients, we recommend new projects start with Serilog or Microsoft.Extensions.Logging.

Installing the Sink

In your application that uses SLAB, install the Seq sink from NuGet:

At the Visual Studio Package Manager console, type:

PM> Install-Package Seq.Client.Slab

This will add the required assemblies to the project.

Now, use the LogToSeq() method to configure an event listener:


The method accepts the URL of your Seq server, and additional parameters like the Seq API key.

Writing Events

That's it! When you write log events to your SLAB log:


They'll appear beautifully in Seq, complete with queryable properties from the payload and ETW.