MailKite for ASP.NET Core

Email for every product you ship — send over a verified domain, receive email as a webhook, give an AI agent its own inbox.
The official MailKite IEmailSender for ASP.NET Core Identity.

Docs · Library guide · mailkite.dev · AI agents

Not yet published. This package lives in the MailKite monorepo (integrations/aspnet-core/) and has not been released to NuGet yet — see docs/integrations/aspnet-core.md ## Releasing for the honest current state. This README describes the package as it will work once shipped.

Install

dotnet add package MailKite.AspNetCore

Targets net8.0 — the minimum ASP.NET Core version that ships Identity's generic IEmailSender<TUser> (used by MapIdentityApi<TUser>()). Depends on the MailKite SDK and Microsoft.AspNetCore.Identity.UI (for the classic, non-generic IEmailSender).

What / why

ASP.NET Core Identity defines IEmailSender (scaffolded Razor Pages UI: dotnet new webapp -au Individual) and, since .NET 8, the generic IEmailSender<TUser> (minimal-API Identity: MapIdentityApi<TUser>()) specifically so account-confirmation and password-reset mail can be swapped in with one interface implementation — the same "swap one interface" wedge as Laravel's Mail::extend and Rails's ActionMailer::Base.add_delivery_method. Without a first-party adapter, a .NET dev integrating MailKite has to hand-wire the .NET SDK into every Identity email hook. This package makes MailKite Identity's email sender: install, set an API key + a from address, and every confirmation/reset email goes out through POST /v1/send via the official MailKite .NET SDK (MailKite, sdks/dotnet) — SDK-first per docs/CODE-SAMPLES.md, never raw HTTP.

Quickstart

Program.cs:

using MailKite.AspNetCore;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddMailKiteEmailSender(builder.Configuration, options =>
{
    options.FromAddress = "hello@yourdomain.com";
    options.FromName = "Your App";
    // ApiKey falls back to the MAILKITE_API_KEY environment variable if left unset here.
});

// ... AddDbContext, AddIdentity/AddIdentityApiEndpoints, etc.

var app = builder.Build();

.env / environment:

MAILKITE_API_KEY=mk_live_...

That's it — AddMailKiteEmailSender registers both:

• IEmailSender (Microsoft.AspNetCore.Identity.UI.Services) for the scaffolded Identity Razor Pages UI (Areas/Identity/...), and
• IEmailSender<TUser> (Microsoft.AspNetCore.Identity) for MapIdentityApi<TUser>()

against the same MailKiteClient and MailKiteEmailSenderOptions, so whichever Identity flavor the app uses just works.

Configuration

MailKiteEmailSenderOptions resolves, in order: the configure delegate passed to AddMailKiteEmailSender, then the "MailKite" section of IConfiguration (if a configuration was passed), then the MAILKITE_API_KEY environment variable for ApiKey.

Option	Required	Notes
ApiKey	Yes (or env var)	A MailKite API key (mk_live_…). Falls back to MAILKITE_API_KEY.
FromAddress	Yes	Verified sending domain address — IEmailSender's methods carry no sender, so it's configured once here.
FromName	No	Display name paired with FromAddress.
BaseUrl	No	Override the API base URL (defaults to https://api.mailkite.dev).

appsettings.json equivalent:

{
  "MailKite": {
    "FromAddress": "hello@yourdomain.com",
    "FromName": "Your App"
  }
}

(Keep ApiKey out of appsettings.json — set it via MAILKITE_API_KEY or user-secrets/Key Vault in production.)

Two ways to register: without configuration binding

builder.Services.AddMailKiteEmailSender(options =>
{
    options.ApiKey = "mk_live_...";       // or leave unset to use MAILKITE_API_KEY
    options.FromAddress = "hello@yourdomain.com";
});

What maps where

ASP.NET Core Identity	MailKite send
IEmailSender.SendEmailAsync(email, subject, htmlMessage)	to, subject, html
IEmailSender<TUser>.SendConfirmationLinkAsync	subject "Confirm your email", html = a link
IEmailSender<TUser>.SendPasswordResetLinkAsync	subject "Reset your password", html = a link
IEmailSender<TUser>.SendPasswordResetCodeAsync	subject "Reset your password", html = the code
MailKiteEmailSenderOptions.FromAddress/FromName	from (both non-generic and generic senders share the same configured from)

Honest failures, not silent drops. MailKiteClient.Send throws MailKiteException (with the API's own error message + HTTP status) on any non-2xx response — an unverified from domain, a suppressed recipient, or a rate limit surfaces to the caller instead of pretending the email went out.

Starter app

A runnable demo wiring this package into real ASP.NET Core Identity (register, confirm email, forgot password) lives in starters/aspnet-core — dotnet run instructions there.

All MailKite libraries

Same contract, every language (full list: https://mailkite.dev/docs/libraries):

Library	Repo	Distribution
MailKite for .NET	mailkite-dotnet	NuGet
MailKite for ASP.NET Core (this package)	mailkite-aspnetcore (not yet mirrored)	NuGet (not yet published)
MailKite for Laravel	laravel	Packagist
MailKite for Node.js	mailkite-node	npm
MailKite for Python	mailkite-python	PyPI
MailKite for Ruby	mailkite-ruby	RubyGems
MailKite for Java	mailkite-java	Maven Central
MailKite for PHP	mailkite-php	Packagist
MailKite for Go	mailkite-go	Go modules

Docs & links

• 📚 Documentation: https://mailkite.dev/docs
• 📦 This package's guide: docs/integrations/aspnet-core.md
• 🤖 AI agents (MCP + inbox agents): https://mailkite.dev/docs/ai-agents
• 🌐 Website: https://mailkite.dev

_{MIT licensed. © MailKite.}