.NET SDK Overview

Introduction

The Smartbills .NET SDK (Smartbills.SDK) provides a strongly-typed C# client for the Smartbills API. It is designed for server-side .NET applications and covers invoicing, file management, and billing operations.

The .NET SDK currently supports InvoiceClient, FileClient, and BillingClient. Additional service clients (expenses, vendors, reports) will be added in future releases. For broader coverage today, consider the JavaScript SDK or Python SDK.

Features

Feature	Description
Strongly Typed	Full C# type definitions for all requests and responses
Async/Await	All methods return `Task<T>` with full `CancellationToken` support
Pagination	Built-in `SBList<T>` response type with pagination metadata
Configurable	Per-request option overrides via `SBRequestOptions`
Invoice Lifecycle	Create, send, void, and summarize invoices
File Operations	Retrieve and update files via the Smartbills file service
Billing	Checkout sessions, customer management, and payment methods
Dependency Injection	First-class ASP.NET Core integration via `Smartbills.SDK.AspNetCore`

Quick Start

Install the package

dotnet add package Smartbills.SDK

Initialize the client

using Smartbills.SDK;

var client = new SmartbillsClient(new SmartbillsClientOptions
{
    AccessToken = "YOUR_API_KEY",
    BusinessId = 123
});

Create and send an invoice

// Create an invoice
var invoice = await client.Invoices.CreateAsync(new InvoiceCreateRequest
{
    CustomerId = 456,
    Items = new List<InvoiceItemRequest>
    {
        new() { Description = "Consulting services", Quantity = 10, UnitPrice = 150.00m }
    },
    DueDate = DateTime.UtcNow.AddDays(30)
});

// Send it to the customer
var sent = await client.Invoices.SendAsync(invoice.Id);

Architecture

The SDK follows a service-client pattern. Each domain area is accessed through a dedicated client property on the main SmartbillsClient instance:

SmartbillsClient
  |-- Invoices   (InvoiceClient)
  |-- Files      (FileClient)
  |-- Billing    (BillingClient)
       |-- CheckoutSessions
       |-- Customers
       |-- PaymentMethods

All methods use long for resource IDs and are fully asynchronous, returning Task<T>. Every method signature includes optional SBRequestOptions and CancellationToken parameters for per-request configuration and cooperative cancellation.

Available Services

InvoiceClient

Full CRUD, send, void, and summary for invoices

FileClient

Retrieve and update files via the Smartbills file service

BillingClient

Checkout sessions, customers, and payment methods

Requirements

Requirement	Minimum Version
.NET	6.0 or later
C#	10.0 or later
NuGet	Latest

Overview

JavaScript / TypeScript

Python

.NET

React

Introduction

Features

Quick Start

Install the package

Initialize the client

Create and send an invoice

Architecture

Available Services

InvoiceClient

FileClient

BillingClient

Requirements

Next Steps

Installation

Usage Guide

​Introduction

​Features

​Quick Start

​Install the package

​Initialize the client

​Create and send an invoice

​Architecture

​Available Services

InvoiceClient

FileClient

BillingClient

​Requirements

​Next Steps

Installation

Usage Guide

Introduction

Features

Quick Start

Install the package

Initialize the client

Create and send an invoice

Architecture

Available Services

Requirements

Next Steps