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Email Capabilities and Features

Core Capabilities​

1. Message Composition​

  • Plain text
  • Rich text (HTML)
  • Formatting (bold, italic, lists)
  • Inline images
  • Signatures

2. Attachments​

  • Multiple file types
  • Size limits (typically 25MB)
  • MIME encoding for binary files
  • Virus scanning

3. Recipients​

  • To (primary recipients)
  • Cc (carbon copy - visible to all)
  • Bcc (blind carbon copy - hidden)
  • Multiple recipients per field

4. Organization​

  • Folders/Labels
  • Archive
  • Search
  • Filters/Rules
  • Tags/Categories

5. Threading​

  • Conversation view
  • In-Reply-To header
  • References header
  • Subject line threading

Advanced Features​

1. Filtering and Rules​

Automatically:

  • Move emails to folders
  • Apply labels
  • Forward messages
  • Delete/archive
  • Mark as read

Example rule:

IF From contains "boss@company.com"
THEN Mark as important AND Forward to mobile

2. Vacation/Auto-Reply​

  • Automatic responses when away
  • Custom messages
  • Date ranges
  • Send once per sender option

3. Email Forwarding​

  • Manual forwarding
  • Automatic forwarding rules
  • Forward as attachment
  • Inline forwarding

4. Email Aliases​

5. Scheduled Sending​

  • Compose now, send later
  • Timezone considerations
  • Cancel before sending

6. Snooze/Reminders​

  • Temporarily hide email
  • Resurface at specified time
  • Reminder notifications

7. Undo Send​

  • Brief window to cancel sent email
  • Typically 5-30 seconds
  • Actually delays sending

Modern Email Features​

1. Smart Compose/Reply​

  • AI-powered suggestions
  • Predictive text
  • Context-aware responses

2. Priority Inbox​

  • Automatic importance detection
  • Machine learning categorization
  • Important/Unread/Everything

3. Unsubscribe​

  • One-click unsubscribe
  • List-Unsubscribe header
List-Unsubscribe: <mailto:unsubscribe@example.com>, <https://example.com/unsubscribe>

4. Spam Filtering​

  • Bayesian filters
  • Machine learning
  • Reputation systems
  • Content analysis
  • User feedback

5. Email Tracking​

  • Read receipts
  • Link clicks
  • Attachment downloads
  • Location tracking

6. Integration Capabilities​

  • Calendar invites (.ics files)
  • Contact cards (vCard)
  • Task creation
  • CRM integration
  • Cloud storage links

7. Mobile Features​

  • Push notifications
  • Offline access
  • Swipe gestures
  • Voice input
  • Biometric authentication

Email Client Types​

1. Desktop Clients​

  • Microsoft Outlook
  • Apple Mail
  • Thunderbird
  • Mailbird

2. Webmail​

  • Gmail
  • Outlook.com
  • Yahoo Mail
  • ProtonMail

3. Mobile Apps​

  • Native email apps
  • Third-party clients
  • Unified inboxes

API and Programmatic Access​

Gmail API​

// Fetch messages
gmail.users.messages.list({
  userId: 'me',
  q: 'is:unread'
})

Microsoft Graph API​

// Send email
await client.api('/me/sendMail')
  .post({
    message: {
      subject: 'Hello',
      body: { content: 'Message' },
      toRecipients: [{ emailAddress: { address: 'user@example.com' }}]
    }
  });

Limitations and Constraints​

  1. Size Limits

    • Attachment size: 25-50MB typically
    • Message size: Including all parts
    • Recipient limits: Varies by provider

  2. Rate Limits

    • Sending limits (e.g., 500/day for Gmail)
    • API quotas
    • Connection limits

  3. Format Support

    • HTML capabilities vary
    • CSS support limited
    • JavaScript blocked for security

  4. Deliverability

    • Spam filters
    • Reputation systems
    • Authentication requirements