---
title: Get started with the .NET client
description: Connect a .NET application to Chronicle and append an event.
---


Use the .NET client when you want direct typed access to Chronicle from a C# application. The smallest useful loop is:

1. create a `ChronicleClient`
2. open an event store
3. append a fact to an event log
4. let projections, reducers, and reactors observe that fact

## Connect

For local development, start the Chronicle kernel and connect with the development connection string.

```csharp
using Cratis.Chronicle;

using var client = new ChronicleClient(ChronicleConnectionString.Development);
var eventStore = await client.GetEventStore("Quickstart");
```

`ChronicleConnectionString.Development` points at the default local Chronicle kernel with development credentials. Use `ChronicleConnectionString.Default` or an explicit `new ChronicleConnectionString("chronicle://...")` when connecting to another environment.

## Define an event

Events are immutable facts. In .NET, mark event records with `[EventType]` so Chronicle can discover and register their schema.

```csharp
using Cratis.Chronicle.Events;

[EventType]
public record BookAdded(string Title, string Isbn);
```

## Append the event

Append the event against the event source it belongs to. The event source id is not part of the event payload; Chronicle stores it in the event context.

```csharp
var bookId = "book-123";

var result = await eventStore.EventLog.Append(
    bookId,
    new BookAdded("The Pragmatic Programmer", "978-0135957059"));

if (!result.IsSuccess)
{
    // Decide whether to retry or surface the append failure to the caller.
}
```

After the append succeeds, Chronicle persists the event and forwards it to the projections, reducers, reactors, and subscriptions that observe the event sequence.

## Use a host integration

For ASP.NET Core and Worker Service applications, prefer the host integration instead of creating the client manually:

```csharp
builder.Services.AddCratisChronicle(options => options.EventStore = "Quickstart");
```

The host integration registers the event store, event log, read models, projections, reducers, reactors, constraints, and related services in dependency injection.

## Next

- [Console quickstart](/chronicle/get-started/console/)
- [ASP.NET Core hosting](/chronicle/get-started/aspnetcore/)
- [Worker Service hosting](/chronicle/get-started/worker/)
- [Shared append semantics](/chronicle/events/appending/)