Pros of proton-mail-android

• Built-in end-to-end encryption for enhanced security
• Seamless integration with ProtonMail's ecosystem
• Regular updates and active development from a dedicated team

Cons of proton-mail-android

• Limited to ProtonMail accounts only
• Less customizable compared to FairEmail
• Closed-source, which may raise privacy concerns for some users

Code Comparison

FairEmail:

private void handleThreadState(EntityMessage message, JSONObject thread) throws JSONException {
    boolean thread_expanded = thread.optBoolean("expanded", true);
    boolean thread_visible = thread.optBoolean("visible", true);
    boolean thread_ignored = thread.optBoolean("ignored", false);
    DB.getInstance(context).message().setMessageThreadState(
            message.id, thread_expanded, thread_visible, thread_ignored);
}

proton-mail-android:

private fun handleMessageState(message: Message, state: MessageState) {
    when (state) {
        is MessageState.Read -> markMessageAsRead(message)
        is MessageState.Unread -> markMessageAsUnread(message)
        is MessageState.Starred -> starMessage(message)
        is MessageState.Unstarred -> unstarMessage(message)
    }
}

The code snippets show different approaches to handling message states. FairEmail uses a more detailed thread state management, while proton-mail-android employs a Kotlin-based state pattern for individual messages.

Pros of Tutanota

• End-to-end encryption for emails, contacts, and calendars
• Cross-platform support (web, desktop, and mobile apps)
• Open-source with a focus on privacy and security

Cons of Tutanota

• Limited customization options compared to FairEmail
• Fewer advanced features for power users
• Closed ecosystem (can't use third-party email clients)

Code Comparison

Tutanota (TypeScript):

export function createMailAddress(address: string): MailAddress {
  const parts = address.split('@')
  return {
    address: address.trim().toLowerCase(),
    name: null,
    contact: null,
    type: null,
    mailAddress: parts[0],
    domain: parts[1],
  }
}

FairEmail (Java):

public static Address[] parseAddresses(Context context, String addresses) {
    List<Address> result = new ArrayList<>();
    for (String address : addresses.split(",")) {
        try {
            result.add(new InternetAddress(address.trim()));
        } catch (AddressException ex) {
            Log.w(ex);
        }
    }
    return result.toArray(new Address[0]);
}

Both repositories focus on email functionality, but Tutanota emphasizes encryption and privacy, while FairEmail offers more customization and advanced features for Android users. The code snippets show different approaches to handling email addresses, with Tutanota using TypeScript and FairEmail using Java.

Pros of Thunderbird

• Backed by Mozilla Foundation, ensuring long-term support and development
• Integrates seamlessly with desktop Thunderbird, providing a unified experience
• Offers a more familiar interface for users transitioning from desktop email clients

Cons of Thunderbird

• Less frequent updates compared to FairEmail
• Larger app size and potentially higher resource usage
• Fewer advanced privacy features than FairEmail

Code Comparison

FairEmail:

private void processMessage(EntityMessage message) {
    try {
        DB db = DB.getInstance(context);
        EntityFolder folder = db.folder().getFolder(message.folder);
        if (folder == null)
            return;
        // ... (additional processing logic)
    } catch (Throwable ex) {
        Log.e(ex);
    }
}

Thunderbird:

private fun processMessage(message: Message) {
    try {
        val folder = accountManager.getFolder(message.folderId)
        if (folder == null) {
            Log.w(TAG, "Folder not found for message ${message.id}")
            return
        }
        // ... (additional processing logic)
    } catch (e: Exception) {
        Log.e(TAG, "Error processing message", e)
    }
}

Both projects handle message processing, but FairEmail uses Java while Thunderbird uses Kotlin. Thunderbird's code appears more concise due to Kotlin's features, while FairEmail's Java code is more verbose but potentially more familiar to some developers.

Pros of Mailspring

• Cross-platform support (Windows, macOS, Linux)
• Modern, user-friendly interface with customizable themes
• Advanced features like mail merge and send later

Cons of Mailspring

• Closed-source core, limiting community contributions
• Requires Mailspring ID for some features
• Higher system resource usage

Code Comparison

Mailspring (JavaScript):

export function sendLater(draft, sendAt) {
  return DatabaseStore.inTransaction(t => {
    draft.metadataForPluginId('send-later').sendAt = sendAt;
    return t.persistModel(draft);
  });
}

FairEmail (Java):

private void onActionSendLater(long id, long when) {
    Bundle args = new Bundle();
    args.putLong("id", id);
    args.putLong("when", when);
    new SimpleTask<Void>() {
        @Override
        protected Void onExecute(Context context, Bundle args) {
            long id = args.getLong("id");
            long when = args.getLong("when");
            DB.getInstance(context).message().setMessageSnoozed(id, when);
            return null;
        }
    }.execute(this, args, "message:snooze");
}

The code snippets show different approaches to implementing a "send later" feature. Mailspring uses JavaScript and a transaction-based approach, while FairEmail uses Java and a task-based system for scheduling messages.

Pros of hydroxide

• Lightweight and focused on providing a bridge for ProtonMail
• Command-line interface offers flexibility for advanced users
• Can be used as a backend for other email clients

Cons of hydroxide

• Limited to ProtonMail, not a full-featured email client
• Requires more technical knowledge to set up and use
• Less user-friendly for non-technical users

Code comparison

FairEmail (Java):

public class EmailProvider {
    private String name;
    private String domain;
    // ...
}

hydroxide (Go):

type Bridge struct {
    pm       *protonmail.Client
    tlsCache *tlsCache
    // ...
}

Key differences

FairEmail is a full-featured Android email client with a graphical user interface, supporting multiple email providers. It focuses on privacy, security, and open-source development.

hydroxide is a ProtonMail bridge that allows using ProtonMail with any IMAP/SMTP client. It's a command-line tool primarily designed for technical users who want to integrate ProtonMail with their existing email setup.

While FairEmail provides a complete email experience for Android users, hydroxide serves as a backend tool for accessing ProtonMail through other email clients. The choice between them depends on the user's specific needs, technical expertise, and preferred email provider.