C# Quickstart

The C# client is generated from your .repost schema into a folder in your project: immutable model classes, a Webhooks.<Catalog>.<Member>Async() method tree, and a shared runtime that owns serialization, retries, idempotency, and delivery outcomes. The same schema and wire format back the TypeScript, Go, Python, and Java SDKs, pinned by a cross-language conformance suite. .NET 8, .NET Framework 4.7.2, or any netstandard2.0 target is supported. The runtime is server-side only — it holds a publish credential and must not ship in a client app.

The runtime package Repost.Client is version 1.0.0 and the schema engine is 0.10.0.

Install the CLI and the runtime package

npm install -g @repost/cli
dotnet add package Repost.Client

curl -fsSL https://repost.sh/install | sh
dotnet add package Repost.Client

Create a schema workspace

repost schema init --language csharp

This scaffolds repost/schema.repost with a starter event and a .env file with an empty REPOST_SEND_API_KEY. A C# generator block sets three things the other languages don’t need — output, namespace, and clientName:

repost/schema.repost

generator sdk {
  language   = "csharp"
  output     = "../Generated"
  namespace  = "Contoso.Events"
  clientName = "RepostClient"
}

enum Currency {
  USD
  EUR
}

type Book {
  /// A book was created
  created
}

model Author {
  name  String
  email String?
}

model Book {
  title    String
  authors  Author[]
  price    Float
  currency Currency
  subtitle String?
}

event BookCreated {
  type      @type(Book.created)
  data      Book
  timestamp DateTime
}

output is resolved relative to the schema file, so ../Generated writes the client to a Generated/ folder next to your .csproj. Code generation explains each field and the build-time MSBuild alternative.

Record the schema and generate

repost schema migrate dev --name init

This records your schema as a migration and generates the client into Generated/ — Client.cs, Descriptors.cs, and Models.cs, plus a copy of the schema and a marker file. The .cs files compile through your project’s default glob, so there is nothing to wire up.

Connect an environment

Create an environment in the dashboard, copy its publish API key into .env, and deploy your schema:

repost auth login
repost schema migrate deploy

Load .env however your app already loads configuration; the runtime reads REPOST_SEND_API_KEY from the environment at send time.

Your first send

The generated client is IAsyncDisposable. Open it with await using; with no ApiKey set the runtime resolves the credential and endpoint from the environment on the first send:

using Repost.Client;
using Contoso.Events;

await using var repost = new RepostClient(new RepostClientOptions());

SendResult result = await repost.Webhooks.Book.CreatedAsync(new BookCreatedInput
{
    CustomerId = "cus_123",
    Data = new Book
    {
        Title = "Dune",
        Authors = new[] { new Author { Name = "Frank Herbert" } },
        Price = 9.99,
        Currency = Currency.Usd,
        Subtitle = "A Desert Epic",
    },
    IdempotencyKey = "book_dune:created",
});

Console.WriteLine(result.Id); // msg_...

new RepostClient(...) validates its options and runs the descriptor-version handshake at construction; a missing credential surfaces on the first send. CustomerId names the customer receiving the event. IdempotencyKey is optional; reusing it with the same payload is safe, and Reliability explains when to pass your own. The compiler rejects unknown events, missing required fields, and wrong types before a send ever leaves your process.

Continue

Code generation

What lands in Generated/, build-time MSBuild generation, and the version handshake.

Configuration

Client options, credential precedence, and transport tuning.

Reliability

Retries, idempotency, the delivery states, and the exception taxonomy.

Send

Schema

Publishing

Delivery

Customer experience

TypeScript

Go

C#

Python

Java

Kotlin

Your first send

Continue

Code generation

Configuration

Reliability

​Your first send

​Continue

Code generation

Configuration

Reliability

Your first send

Continue