Authentication

Configure your Paubox API credentials for the C# SDK.

Obtain your credentials

The Email API client requires two credentials:

• API key: a secret token that authenticates your requests
• Username: your Paubox API endpoint username (not your login email)

Both are available in the Paubox dashboard under API Credentials.

Option 1: Constructor parameters

Pass credentials directly; useful for console apps or when managing secrets via environment variables:

var emailLib = new EmailLibrary("YOUR_API_KEY", "YOUR_USERNAME");

Read from environment variables:

var emailLib = new EmailLibrary(
    Environment.GetEnvironmentVariable("PAUBOX_API_KEY"),
    Environment.GetEnvironmentVariable("PAUBOX_API_USER")
);

Option 2: IConfiguration (recommended for ASP.NET Core)

Add your credentials to appsettings.json:

{
  "APIKey": "YOUR_API_KEY",
  "APIUser": "YOUR_USERNAME"
}

Then inject IConfiguration and pass it to the constructor:

// In Program.cs or Startup.cs
builder.Services.AddSingleton<IEmailLibrary>(sp =>
{
    var config = sp.GetRequiredService<IConfiguration>();
    return new EmailLibrary(config);
});

Or instantiate directly:

var emailLib = new EmailLibrary(configuration);

The SDK reads APIKey and APIUser from the configuration and sets the Authorization header automatically on every request:

Authorization: Token token=YOUR_API_KEY

Forms client

FormsLibrary requires no credentials. Instantiate it with no arguments:

var formsLib = new FormsLibrary();

Use IFormsLibrary in ASP.NET Core for dependency injection and testability:

builder.Services.AddSingleton<IFormsLibrary, FormsLibrary>();

Security notes

• Never hard-code credentials in source files. Use appsettings.json with user secrets or environment variables.
• Use .NET user secrets during development to keep credentials out of source control.