Missive Alternatives

Thunderbird

Thunderbird is a free, open source, cross-platform e-mail, news and instant messaging client. The project strategy is modeled after Mozilla Firefox.

Features:

• Extensible by Plugins/Extensions
• Support for IMAP
• Built-in RSS reader
• Encryption
• SMTP integration
• Add-ons
• Calendar integration
• Extensions
• Multiple Account support
• Protected by Password
• Tabs
• Built-in Calendar
• Categories
• Customizable
• Delivery reports
• Extensible by Plugins/Extensions
• Free API
• Gmail integration
• Google Calendar integration
• Import from Google Reader
• Gui
• HTML Compose
• Integrated Chat
• Integrated Password Manager
• Integrated Web Browser
• Intuitive
• Legacy addons support
• Export to OPML
• Import feeds from OPML
• Organize mails
• POP3 Support
• Portable
• Secure File Sharing
• Support for POP3
• Tabbed interface
• Support for Themes

Microsoft Office Outlook

Part of the Microsoft Office Suite, Outlook is a personal information manager that lets you manage your e-mail, calendar, contacts, and tasks.

Features:

• Address book integration
• Built-in Calendar
• Calendar integration
• Exchange
• Box.com integration
• Contacts
• Custom rules
• Dropbox integration
• Email scheduling
• Exchange Integration
• Flight Status
• Gmail integration
• ICloud Integration
• Integrated Search
• Multiple Account support
• Night mode/Dark Theme
• Office 365 integration
• Onedrive integration
• Organize mails
• Shared calendars
• Signature with image
• Smart attachments
• Todos
• Unified inbox
• Yahoo Integration

Spark

E-mail app with all the great features: swipes (long/short), snooze, add (multiple) attachments from the cloud, support for various e-mail services and more.

Features:

• Clean design
• Multiple Account support
• Sync across Devices
• Calendar integration
• Email scheduling
• Exchange
• Postpone email reception
• Smart inbox
• Snooze mail

Front

Front is the first email management software for teams that integrates with the tools you already use. With Front, you can assign messages to teammates, write comments...

Features:

• Shared inbox
• Comment section
• Customer service
• Email tracking
• Real time collaboration
• Team Collaboration

Spike

Bring your workspace together into one unified app. It’s everything your team has been looking for in a productivity and messaging app, but easier, and all with your...

Features:

• Built-in File Manager
• Send later
• Unified inbox
• Google Chrome Extensions
• Night mode/Dark Theme
• Priority Inbox
• Snooze reliability
• Tags
• Undo send
• Web-Based
• Built-in Calendar
• Built-in translation
• Bulk actions
• Chat
• Cloud sync
• Conversational email approach
• Dropbox integration
• Email Archiving
• Encrypted Email
• Encrypted chat
• Exchange Integration
• File Compression
• File Searching
• Gmail integration
• Google Drive integration
• Group chat
• Group collaboration
• ICloud Integration
• Integrated Chat
• Live Preview
• Multiple Account support
• Office 365 integration
• Organize mails
• Outlook integration
• Image Preview
• Real time collaboration
• Real-time monitoring
• Real-time tracking
• Secure Chat
• Suggested replies
• Team Collaboration
• Threaded Conversations
• Unified Calendar
• Unified search
• Video calling
• Video chat
• Video streaming
• Yahoo Integration

Plumm

Single collaborative customer support dashboard for all of your projects. Chat with your customers and your team members using single workspace. If it's an email...

Features:

• Customer support
• Helpdesk ticketing
• Real time collaboration
• Shared inbox
• Live Chat
• Team messaging

Mailbox for Zoho

Multi-Account Zoho client for Mac.

SharedBox

Your conversations already happen in Slack, why not your shared inbox? Collaborate on emails, comment, add notes and reply directly from Slack.

Features:

• Customer support
• Slack integration

TouchMail

Navigate messages with zooms and swipes across your messages. Turn your email into colorful, visual tiles you can explore with your fingers or mouse. Rich 3D...