Outlook: free alternatives at a glance

Many users choose Outlook as their e-mail client and PIM (Personal Information Manager). As a component of the Microsoft Office suite, it is often a standard solution (in connection with the Microsoft Exchange Server) for businesses. Many freelancers and small companies cannot afford solutions intended for large businesses, but there are numerous e-mail management programs besides Outlook that are available for free.


The Mozilla mail client Thunderbird is certainly one of the most frequently used Outlook alternatives - both among private users and in companies. The open source solution is also available free of charge. The basic version of the program is rather streamlined and provides you with the most used basic functions.

The most important facts at a glance:

  • Free open-source solution
  • Available for Windows and Mac
  • Encryption possible
  • Administration of RSS feeds possible

A big plus: Numerous add-ons are available. This means that the email program can be expanded for example with modules for date and task administration. However, the add-ons and extensions are always tailored to the respective version. If you want to update your version of Thunderbird, you must also update add-ons, or wait until the appropriate versions are available. Here are the advantages and disadvantages of Thunderbird at a glance:

Pros Cons
Clear structure Becomes unclear quickly if user if demanding and over-uses the possibilities
Practical functions for message management and categorisation Add-ons must be updated separately
Individually expandable through numerous add-ons  


SeaMonkey presents an all-round solution for office communication. It also includes an HTML editor as well as a browser, e-mail, and chat client. Mail organisation is carried out via instructions defined by the user and further features such as flexible sorting and visual highlighting are also available. The encryption takes place according to S/MIME. SSL/TLS encryption must first be activated manually.

The most important facts at a glance:

  • Available for Windows, Mac, and Linux
  • Read receipts
  • Digital signature
  • Integration in LDAP directory services
  • Customisable spam filter
  • Administration of several accounts possible

For a non-commercial open-source project, SeaMonkey users get an enormously comprehensive Outlook alternative that goes far beyond the actual function of an email client. SeaMonkey is basically many different Mozilla projects bundled together.

Pros Cons
High security standards Irregular updates
Very comprehensive complete office package Several functions need to be manually activated
Many important functions for the corporate environment, e.g. digital signature or acknowledgement of receipt  


The electronic organiser Evolution is an e-mail and groupware program that has proved very popular among Linux users as a free Outlook alternative. It supports all the important functions that Outlook offers: In addition to the administration of e-mail traffic, contacts, appointments, tasks and notes can also be organised.

The most important facts at a glance:

  • Available for Linux
  • Adaptive junk email filter
  • Connection with Microsoft Exchange Server possible
  • RSS reader

The encryption takes place via GPG and S/MIME. Evolution is also suitable for professional use, and collaboration servers and the Microsoft Exchange Server are supported.

Pros Cons
Suitable for professional use Many interfaces linking to calendars or contact databases of other services
Interface easy to understand with only a few limitations  


The client Spike was released in 2013 and combines the functions of classic e-mail programs with those of modern messenger apps. As soon as you link a private mailbox to the app, cumbersome elements such as subject lines or signatures become a thing of the past, while the elementary mail client functions - such as the central inbox, calendar, or contact management - are integrated into the modern messenger environment. It is no coincidence that the manufacturer describes Spike as a “conversational e-mail app.”

The most important facts at a glance:

  • Available for Windows, Mac, iOS, and Android as well as web applications
  • Collaboration features such as group chats
  • Connections to cloud services such as Google Drive, Dropbox and OneDrive
  • Integrated file manager

Spike also relies on modern standards when it comes to security: With a single click, any communication including attached files can be encrypted (AES-256), so that your messages are optimally protected against unauthorised access. Recipients who do not use the app can also decrypt the received messages with a single click. Unlike Outlook, Spike is free for private users - monthly fees are charged for integrating business email accounts.

Pros Cons
Cross-platform thanks to web app No dark theme for desktop
Easy linking between mail and messenger No third party integrations
Team features are integrated by default  

eM Client

The program eM Client is an e-mail client for private and business use. Like its predecessors in the list, the free program for Windows and macOS offers standard functions for appointments and contact management, as well as an integrated instant messenger. However, free use without any restrictions is only for private users: commercial use as well as the use of more than two accounts require you to purchase the Pro license.

The most important facts at a glance:

  • Available for Windows and Mac
  • RSS reader
  • Integrated Instant messenger
  • Automatic updates

The program supports all major basic services, including Gmail, Exchange, iCloud, and Outlook. The list of supported email technologies also includes POP3, SMTP, IMAP, EWS, and AirSync. Some additional features such as the translation function and the extremely fast full test search function make everyday work easier. Secure communication is ensured via SSL/TLS standards, encryption is via S/MIME.

Pros Cons
High security standards Free version only for up to two accounts and for private use only
Many synchronisation features  
Smooth date import  
Touch support  


An Outlook alternative that is completely free of charge for private users (companies pay either a one-time fee or an annual fee) is the Mailbird available for Windows. The email solution allows you to unify and manage your messages and contacts from multiple accounts into a single inbox. With lots of free themes, you can design the interface according to your wishes.

The most important facts at a glance:

  • Available for Windows
  • Drag-and-drop contact manager
  • Powerful attachment search function
  • Shortcut keys for various actions such as writing, replying, forwarding, etc.

Mailbird provides interfaces to numerous apps, enhancing your mailbox with useful features for organisation, interaction, and teamwork. For example, you can integrate WhatsApp, Twitter, Google Calendar, Dropbox, and Slack into your email client to transform it into a multi-functional platform.

Pros Cons
Modern, attractive design No filter function
Integration of various additional tools such as Slack or WhatsApp possible Some features are missing in the free edition
Snooze function  

Pegasus Mail

Pegasus Mail is one of the original e-mail programs – it’s been around since 1989 and is continuously being developed further. The mail client supports mailboxes in UNIX format and is regarded as a simple, but powerful, and above all, free Outlook alternative. Pegasus is POP3 and IMAP4 compatible and also supports SMTP, LDAP, PH, and SSL.

The most important facts at a glance:

  • Available for Windows
  • Sophisticated filter function

Don't be fooled by Pegasus’ simple and rather unspectacular design. The program is not only very clear and easy to use, it also offers some practical additional functions, such as a sophisticated, programmable filter function. The mail service offers a mass mail function that can not only be used by private users, but also for marketing purposes.

Pros Cons
Simple, but powerful Complicated configuration
High security standards Less attractive user interface
Freely programmable filter function  


As the last alternative to Outlook, we present the product MICROSOFT® EXCHANGE Hosting BY 1&1 IONOS. Microsoft® Exchange Server is a groupware system that enables access to contacts, appointments, and e-mail databases within a company from anywhere in the world. In short, you can open Microsoft Office anywhere you want.

The Exchange server can also be obtained directly from Microsoft®. However, the hosted exchange solution from 1&1 IONOS is considerably beneficial to a company’s IT department. It saves the cost of purchasing a sophisticated IT infrastructure. MICROSOFT® EXCHANGE Hosting BY 1&1 IONOS provides the required server infrastructure from 1&1 IONOS.

What the 1&1 IONOS offer also includes is an all-round carefree package: In addition to the Outlook software as a desktop version and the management of mailboxes via Microsoft Exchange, you also receive your own e-mail domain.

The most important facts at a glance:

  • Management of inboxes via Microsoft Exchange
  • Microsoft Outlook software
  • Real-time synchronisation
  • Mobile access to all data
  • 25 GB mailbox storage for each employee

The Microsoft Exchange package minimises the acquisition costs for a server structure and offers even more advantages: The administration effort is reduced because the provider takes care of mailbox maintenance, updating virus scanners and spam filters and continuously running software updates. All data is hosted on security servers with a specially secured infrastructure. If you are looking for a professional e-mail client solution, the 1&1 IONOS variant is a good Outlook alternative - even if it is not available free of charge per se.

The offer may be too extensive for private users, but it is a good option for freelancers and entrepreneurs and especially for small and medium-sized companies. If you understand the importance of a professional appearance and high security standards, then you’ll benefit from an ideal price-performance ratio.

Pros Cons
Individual e-mail domain included Not a free Outlook alternative
Highest security standards Not suitable for private users
Hardware acquisition and administration taken care of by provider  
Microsoft Outlook software is included in package  

Overview of all mail clients

  Available for Portable version Security Supports Digital signature License Price
Thunderbird Windows, Mac OS X, Linux... PGPS/MIME POP, POP3, IMAP, SMTP, NNTP, IPv6 MPL/GPL/LGPL Free
Spike Windows, macOS, iOS, Android AES-256 IMAP - Freeware, proprietary Free, but use is limited
  Windows - SSLT/TLS, S/MIME POP3, IMAP, SMTP,EWS Freeware, proprietary Free, but use is limited
Mailbird Windows - SSL/TLS POP3, IMAP, SMTP Freeware, proprietary Free, but use is limited
Pegasus Mail Windows - S/MIME, OpenSSL POP3, IMAP4, SMTP, NNTP, LDAP v2 Freeware, proprietary Free
MICROSOFT® EXCHANGE Hosting BY 1&1 IONOS Windows, macOS n/a POP3, IMAP4, SMTP, LDAP v2 - $6/month for first year, then $10/month

Outlook alternatives for mobile devices

Outlook is not usually the first choice for mobile internet users. Depending on the operating system, smartphones and other mobile devices come equipped with e-mail programs, calendars, and contact management functions. The pre-installed apps are a good solution for private users and Google apps are especially popular on Android devices. The same also applies to businesses, which increasingly consider Google products as the go-to choice. Synchronising different apps, calendars, e-mails, and contacts is not complicated and Apple users can use pre-installed products and dock these onto an Exchange account or a Google app.


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