MailFoundation is a Swift package that provides IMAP, POP3, and SMTP client stacks plus mail metadata utilities. It is designed to pair with MimeFoundation for MIME parsing and message construction while providing a focused, protocol-level foundation for mail applications and services.
This project is a port of the .NET Foundation mail stack originally created by Jeffrey Stedfast MailKit/MimeKit. The goal is to bring those capabilities and API ergonomics to Swift developers, with modern async/await support and a Swift-native type system.
- IMAP, POP3, and SMTP client stacks with sync and async APIs.
- Async mail stores and transports (
AsyncImapMailStore,AsyncPop3MailStore,AsyncSmtpTransport). - SASL authentication including SCRAM, NTLM, GSSAPI, CRAM-MD5, and XOAUTH2.
- STARTTLS and TLS support via Network framework, POSIX sockets, or OpenSSL.
- Proxy support (SOCKS4/5, HTTP CONNECT).
- Search and threading helpers (
SearchQuery,MessageThreader, threading references). - Retry policies, timeouts, and connection pooling.
- Protocol logging and authentication secret redaction.
- Swift 6.2+
- macOS 10.15+ (visionOS 1.0+ per Package.swift)
Add the package to your Package.swift dependencies:
dependencies: [
.package(url: "https://github.com/migueldeicaza/MailFoundation", branch: "main")
]Then add MailFoundation to your target dependencies:
targets: [
.target(
name: "YourApp",
dependencies: [
"MailFoundation"
]
)
]import MailFoundation
let store = try AsyncImapMailStore.make(
host: "imap.example.com",
port: 993,
backend: .network
)
try await store.connect()
_ = try await store.authenticate(user: "user@example.com", password: "secret")
_ = try await store.openInbox(access: .readOnly)
let results = try await store.search(.all)
print("Found \(results.ids.count) messages")
await store.disconnect()import MailFoundation
import MimeFoundation
let transport = try AsyncSmtpTransport.make(
host: "smtp.example.com",
port: 587,
backend: .network
)
try await transport.connect()
_ = try await transport.ehlo(domain: "client.example.com")
_ = try await transport.authenticate(SmtpSasl.plain(
username: "user@example.com",
password: "secret"
))
let message = MimeMessage()
message.from.add(MailboxAddress(name: nil, address: "sender@example.com"))
message.to.add(MailboxAddress(name: nil, address: "recipient@example.com"))
message.subject = "Hello"
message.body = TextPart("plain", "Hello, World!")
_ = try await transport.send(message)
await transport.disconnect()Full API documentation is available at https://migueldeicaza.github.io/MailFoundation/.