Outlook alternatives: free and fee-based alternatives compared

Many users choose Outlook as their email 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 email management programs besides Outlook that are available for free.

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Overview of all free and fee-based Outlook alternatives

  Available for Security Supports Digital signature License Price
Postbox Windows,macOS PGP POP,
Yes Proprietary Fee-based
Thunderbird Windows, macOS, Linux and other OS PGP
SeaMonkey Windows, macOS, Linux S/MIME
Evolution Linux PGP, S/MIME POP3, IMAP, SMTP, NNTP, LDAP Yes LGPL Free
Spike Windows, macOS, iOS, Android AES-256 IMAP, SMTP Yes Freeware, proprietary Limited free use
eM Client Windows, mac SSL/TLS, S/MIME, PGP POP3, IMAP, SMTP, EWS Yes Freeware, proprietary Limited free use
Mailbird Windows SSL/TLS POP3, IMAP, SMTP Yes Freeware, proprietary Fee-based
Pegasus Mail Windows S/MIME, OpenSSL POP3, IMAP4, SMTP, NNTP, LDAP v2, MHS Yes Freeware, proprietary Free
IONOS Hosted Microsoft Exchange Windows, macOS, iOS, Android S/MIME POP3, IMAP4, SMTP, LDAP v2 Yes Proprietary Fee-based
Google Workspace Windows, macOS, Linux, iOS, Android n/a POP3, IMAP4, SMTP, LDAP v2 Yes Proprietary Fee-based
Zimbra Windows, macOS, Linux S/MIME POP3, IMAP, SMTP ? Open Source & proprietary Free and fee-based
Spark iOS, iPadOS, Android, macOS n/a IMAP, SMTP Yes Freeware, proprietary Free
Mailspring Windows, macOS, Linux n/a IMAP, SMTP Yes Freeware, proprietary Limited free use

All information up to date as of January 2022.

Outlook alternatives in detail


Postbox was created by former Mozilla employees and therefore was originally based on Thunderbird. More than ten years later, the software has evolved into an independent and powerful mail client. The design of the interface is similar to that of other solutions and intuitive to use. Users who prefer a different look can simply adjust themes or create their own design templates.

The most important facts at a glance:

  • Easy to use
  • Help with drafting emails
  • HTML editor for emails

For a more productive workflow, Postbox uses various shortcuts. Users can access the Quick Bar via hotkey in order to quickly move or categorize messages, for example. When composing an email, you can insert a signature via Quick Bar without using the mouse.

Writing emails in Postbox has several other advantages. The software comes with numerous templates and text blocks to help you write professional cover letters and replies. You can also create your own and add placeholders where the recipient’s name is automatically added.

Advantages Disadvantages
✔ Intuitive interface ✘ Not a free Outlook alternative
✔ Quick workflow thanks to Quick Bar ✘ PGP encryption only available via add-on
✔ Templates available to draft professional emails  
✔ HTML editor for emails  


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, Mac and LInux
  • 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 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:

Advantages Disadvantages
✔ Clear structure ✘ Becomes unclear quickly if user if demanding and over-uses the possibilities
✔ Practical functions for message management and categorization  
✔ Individually expandable through numerous add-ons  


The client Spike was released in 2013 and combines the functions of classic email programs with those of modern messenger apps. As soon as you link a private mailbox to the app, irritating 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 email app”. Audio and video calls are also possible via the software.

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
  • Create and share notes, tasks and to-do lists

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 unauthorized 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.

Advantages Disadvantages
✔ Cross-platform thanks to web app ✘ Doesn't support pop3 accounts
✔ Easy linking between mail and messenger ✘ No third party integrations
✔ Team features are integrated by default ✘ Expensive for companies
✔ Dark theme for desktop  
✔ Voice messaging  
✔ Advanced search  


SeaMonkey presents an all-round solution for office communication. It also includes an HTML editor as well as a browser, email, and chat client. Mail organization 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
  • Customizable 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.

Advantages Disadvantages
✔ 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 organizer Evolution is an email and groupware program that has proved very popular among Linux users as a free Outlook alternative. As part of the GNOME desktop environment, it’s become a standard mail client for many Linux users. It supports all the important functions that Outlook offers: In addition to the administration of email traffic, contacts, appointments, tasks, and notes can also be organized.

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.

Advantages Disadvantages
✔ Suitable for professional use ✘ Many interfaces linking to calendars or contact databases of other services
✔ Interface easy to understand with only a few limitations  

eM Client

The program eM Client is an email 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 free option is missing a couple of important features.

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 text search function make every day work easier. Secure communication is ensured via SSL/TLS standards, encryption is via S/MIME.

Advantages Disadvantages
✔ High security standards ✘ Free version only for up to two accounts and for private use only
✔ Many synchronization features ✘ Free version does not have all features
✔ Smooth date import  
✔ Touch support  
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An Outlook alternative that is only free in the test version is 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 organization, 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.

Advantages Disadvantages
✔ Modern, attractive design ✘ No filter function
✔ Integration of various additional tools such as Slack or WhatsApp possible ✘ No free edition available
✔ Snooze function  

Pegasus Mail

Pegasus Mail is one of the original email 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. The software is available free to use for private users with optional donations for developers. A commercial license can be purchased.

Advantages Disadvantages
✔ Simple, but powerful ✘ Complicated configuration
✔ High security standards ✘ Less attractive user interface
✔ Freely programmable filter function  

IONOS Hosted Microsoft Exchange

As another alternative to Outlook, we present the product Hosted Microsoft Exchange from IONOS. Microsoft is a groupware system that enables access to contacts, appointments, and email 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 IONOS is considerably beneficial to a company’s IT department. It saves the cost of purchasing a sophisticated IT infrastructure. Hosted Microsoft Exchange from IONOS provides the required server infrastructure.

What the 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 email domain.

The most important facts at a glance:

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

The Microsoft Exchange package minimizes 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 email client solution, the 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.

Advantages Disadvantages
✔ Individual email 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  

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Google Workspace (formerly G Suite)

The Internet giant Google is also offering its own Outlook alternative. Google Workspace (formerly G Suite) is a comprehensive office package, designed for professional use. In addition to Gmail, Google’s email service, suite users have access to text creation platforms and cloud storage collaboration tools. Many users already use one or more of these apps in a free version. Gmail’s freemail service is particularly popular. However, if you opt for the fee-based Google Workspace, you will receive full access to each application’s range of functions, and can also secure a professional email connection for business communication.

In contrast to their freemail offer, Gmail offers ad-free access to work platforms and professional management through Google Workspace. Company administrators can manage their employees’ accounts centrally, and subsequently adapt them individually to the company’s needs. This includes assigning roles.

The most important facts at a glance:

  • Part of a large office suite
  • Software-as-a-service
  • Plenty of storage space
  • Web interface
  • Mobile apps for iOS and Android
  • GDPR compliant

Google Workspace can be operated entirely through a web interface. Just like you’re accustomed to with Google, the controls are very clear and the user can quickly reach all functions. With regards to features, since it’s a suite, all the apps are closely connected. For example, you can easily move file attachments to cloud storage and edit them there with Google Docs. Scheduling appointments or holding online meetings also works with Gmail thanks to extensive integrations.

Users can purchase the Google Workspace through IONOS. No matter which of the two monthly rates you choose, a professional email address with a self-selected ending is included for the first year. Of course, access to all Google apps is also available.

Advantages Disadvantages
✔ Platform-independent ✘ Not a free Outlook alternative
✔ Full Office Suite  
✔ Mobile apps  
✔ GDPR compliant  

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The Outlook alternative Zimbra is available in different editions. Zimbra is a groupware solution that caters mostly to companies. Synacor, its maker, provides two different versions: a premium suite and an open-source solution. Both options are aimed at working together as part of team. The free version offers considerably fewer features. Zimbra 9, the premium solution, boasts a broad range of features. Besides email functions, the package also includes options to chat with team members, video calling, filesharing, and other practical solutions.

When you need a free email client, Zimbra Desktop is the right choice. The software is a groupware solution and is compatible with Windows, macOS, and Linux. It can be used via an app. The server software runs on different Linux configurations. It provides access to a calendar, to-do list and an address book – similar to other Outlook alternatives. Zimbra Desktop allows you to manage multiple email accounts by different providers without losing sight of them.

The most important facts at a glance:

  • Free to use
  • Multiple account option
  • Many practical features
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What makes Zimbra stand out are Zimlets. These are extensions of the mail client, which can be optical features, useful functional extensions or extensive administrative tools.

Advantages Disadvantages
✔ Large groupware solution ✘ Too extensive for private users in the groupware solution
✔ Available as free open source option  
✔ Extendable functions with Zimlets  


Email client Spark supports user workflow. The app relies on intelligent functions that help to avoid disruption and speed up important processes. The app’s highlight is a filter: the software shows notifications only if a sender is already known. The filter can detect newsletters and sort them into their own category. The app also offers a function to react more rapidly to incoming emails or put others “on hold”. When you can’t reply to an email immediately, the app reminds you later.

Spark has been created with teamwork in mind. It includes features that enable users to discuss emails together. Each member of the team can comment without an external party being able to see their comments. The delegation function is another innovative inclusion. Members can assign the writing of an email to others in their organization. Naturally, Spark also includes a calendar.

The most important facts at a glance:

  • free
  • innovative features for teamwork
  • intelligent filters

Currently, Spark is only available for macOS and mobile devices. A Windows version and a web app are already in the planning. If you’re interested in using one these options, you can sign up to Spark’s newsletter to receive an alert when they become available.

The app can be downloaded for free. It offers 5 GB storage space for the team. For larger teams, a premium version can be purchased. This includes more storage space and additional features.

Advantages Disadvantages
✔ Free email client ✘ Not available for Windows
✔ Many team functions  
✔ Intelligent filters  
✔ 5 GB storage for teams  


Mailspring is a free outlook alternative that focuses on providing a multi-lingual service. The software is available in multiple languages (in some cases machine-translated) and enables the translation of emails. Besides English and German, Mailspring currently translates into four additional languages. It also provides a spellchecking tool for these languages.

Further, the software provides all the features one would expect from an email client. The search function is rather impressive. Multiple email accounts can easily be integrated and social media accounts can be added. Users can also add information from LinkedIn or Twitter to their contacts. The activity tracking is an interesting feature which shows users whether a sent email has already been read. However, the feature is only available in the paid-for edition alongside other interesting tools.

The most important facts at a glance:

  • focus on multiple languages
  • activity tracking
  • clean interface
Advantages Disadvantages
✔ Translation function ✘ Few extra features in free version
✔ Many language versions available  
✔ Tracking functions  
✔ Extensive contacts section  

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 email 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. Synchronizing different apps, calendars, emails, 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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