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The Best Outlook Alternatives: Complete Email Client Guide

The InfoSwitch Team 31 janvier 2026 13 min read

Microsoft Outlook is the most widely used email client in the business world, but it is neither the only one nor necessarily the best. Whether you\'re looking for a free alternative, something lighter, more privacy-friendly, or simply different, this guide reviews all the options available in 2026.

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Why Look for an Alternative to Outlook?

Outlook is powerful, but it has several drawbacks that push many users to look elsewhere:

Size and Complexity

Outlook is a heavy application that consumes a lot of resources. On a modest computer, it can significantly slow down the system. Moreover, its interface is complex with many features that most users never use.

Cost

Outlook is part of Microsoft 365, which costs between 7€ and 22€ per month per user. For simply reading and sending emails, that\'s often disproportionate.

Privacy

Microsoft collects data on your Outlook usage and emails pass through its American servers. For privacy-conscious users, this is problematic.

Ecosystem Lock-In

Outlook works best with other Microsoft products. If you use other services (Google Calendar, Infomaniak storage...), integration is less smooth.

Free Alternatives

Thunderbird: The Open Source Standard

Mozilla Thunderbird is the most complete and popular open-source email client. Developed by the Mozilla Foundation (Firefox), it is entirely free and respectful of your privacy.

  • 100% free – No paid version, no restricted features
  • Multi-account – Manage all your emails in a single interface
  • Built-in calendar – CalDAV compatible (Infomaniak, Google, etc.)
  • Extensions – Hundreds of add-ons for customization
  • Cross-platform – Windows, Mac, Linux

Strengths

Free, open source, privacy-friendly, very complete, large community, excellent IMAP/CalDAV support.

Weaknesses

Less modern interface than competitors, no official mobile version, sometimes complex configuration.

Thunderbird + Infomaniak

Thunderbird integrates perfectly with Infomaniak services: IMAP email, CalDAV calendar, CardDAV contacts. Configuration is automatic thanks to auto-discovery.

Ideal for: Advanced users, Linux professionals, privacy-conscious individuals, limited budgets.

Apple Mail: Perfect macOS/iOS Integration

If you\'re in the Apple ecosystem, Apple Mail is the most natural option. Pre-installed on Mac, iPhone, and iPad, it offers unmatched system integration.

  • Elegant and consistent native interface
  • Automatic iCloud synchronization
  • Spotlight, Siri, and notification integration
  • IMAP, Exchange, iCloud Mail support
  • Privacy features (IP address masking)

Strengths

Free, perfect system integration, smooth Mac/iPhone sync, clean interface, privacy protection.

Weaknesses

Apple-only, limited features vs Outlook, no snooze, sometimes unreliable search.

Ideal for: Mac/iPhone users who want simplicity and system integration.

Windows Mail: The Default Choice

The built-in Mail app in Windows 10/11 is a simple and lightweight option for basic use.

  • Pre-installed, no complex configuration
  • Modern and clean interface
  • Synchronization with Windows Calendar
  • Multi-account support (Outlook, Gmail, IMAP)

Ideal for: Basic personal use, undemanding Windows users.

Paid Alternatives

Spark: Productivity Reinvented

Spark by Readdle has become one of the most popular email clients thanks to its innovative productivity features. Available on Mac, iOS, Windows, and Android.

  • Smart Inbox – Automatic sorting by importance (personal, notifications, newsletters)
  • Snooze – Postpone an email for later
  • Scheduled Send – Schedule sending at the ideal time
  • Collaboration – Draft emails as a team, delegate
  • Built-in AI – Summaries, reply suggestions
Plan Price Features
Free Free Basic personal use
Premium 4.99€/month AI, templates, integrations
Teams 6.99€/user/month Collaboration, administration

Privacy Warning

Spark stores your email credentials on its servers to enable certain features (push, sync). If confidentiality is crucial, choose Thunderbird or a client that stores nothing in the cloud.

Ideal for: Busy professionals, collaborative teams, users who receive a lot of emails.

eM Client: The Most Complete Windows Alternative

eM Client is a Czech email client that positions itself as the direct alternative to Outlook on Windows and Mac.

  • Outlook-like interface (ribbon, panes)
  • Integrated email, calendar, tasks, contacts
  • Exchange, Office 365, Google support
  • Built-in PGP encryption
  • Automatic email translation
Plan Price Features
Free Free 2 accounts max, basic features
Pro 49.95€ (perpetual license) Unlimited accounts, all features

Strengths

Very complete, perpetual license (no subscription), good Outlook alternative, familiar interface.

Weaknesses

Limited free version, no Linux version, slightly dated interface.

Ideal for: Outlook users looking for a cheaper alternative with a perpetual license.

Mailbird: Design First

Mailbird focuses on a modern interface and integrations with popular apps (Slack, Trello, WhatsApp...).

  • Clean and customizable interface
  • Numerous integrations (apps, social networks)
  • Fast reading with preview
  • Snooze and scheduled send
  • Fast search
Plan Price
Personal 2.28€/month (annual)
Business 4.58€/month (annual)
Lifetime 79€ (perpetual license)

Ideal for: Windows users who appreciate modern design and integrations.

Mailspring: The Open Source Compromise

Mailspring is a modern email client based on the Nylas Mail project (discontinued). It offers a good balance between features and simplicity.

  • Modern and responsive interface
  • Email open tracking (read receipts)
  • Snooze and reminders
  • Customizable themes
  • Cross-platform (Windows, Mac, Linux)
Plan Price Features
Free Free Basic features
Pro $8/month Tracking, templates, snooze

Ideal for: Linux users wanting a modern interface, sales teams (tracking).

Webmail Clients

If you prefer accessing your emails via a browser, without installing software:

Infomaniak Webmail

Infomaniak\'s webmail is an excellent, modern, and complete option:

  • Intuitive and responsive interface
  • Integrated calendar and contacts
  • Fast search
  • Advanced filters and rules
  • HTML signatures

Create an Infomaniak Email Address

Roundcube

An open-source solution used by many hosting providers. Classic but effective interface.

ProtonMail (Web)

For those who prioritize confidentiality, ProtonMail\'s web interface offers native end-to-end encryption.

Full Comparison

Client Price Platforms Strengths Use Case
Thunderbird Free Win/Mac/Linux Complete, open source Advanced use, Linux
Apple Mail Free Mac/iOS Apple integration Apple ecosystem
Spark Free/4.99€ Win/Mac/iOS/Android Smart Inbox, AI Productivity, teams
eM Client Free/49.95€ Win/Mac Complete, perpetual Outlook alternative
Mailbird 2.28€/month Windows Design, integrations Design-focused users
Mailspring Free/$8 Win/Mac/Linux Modern, tracking Linux, sales teams

Selection Criteria

1. Your Operating System

  • Windows: eM Client, Thunderbird, Mailbird, Spark
  • Mac: Apple Mail, Spark, Thunderbird, eM Client
  • Linux: Thunderbird (the only truly complete choice), Mailspring
  • Mobile: Spark, Outlook mobile, Gmail, native client

2. Your Required Privacy Level

Maximum Privacy

Choose Thunderbird, which communicates nothing to third-party servers. Avoid Spark, which stores your credentials in its cloud.

3. Your Budget

  • 0€: Thunderbird, Apple Mail, Windows Mail
  • Under 50€ one-time: eM Client Pro, Mailbird Lifetime
  • Subscription: Spark Premium, Mailspring Pro

4. Your Collaboration Needs

If you work as a team on emails:

  • Spark Teams – Native collaboration, delegation
  • Front – Dedicated solution for support teams
  • Missive – Collaborative shared inbox

Configuration with Infomaniak

All the email clients mentioned are compatible with Infomaniak accounts. Here are the configuration settings:

Infomaniak IMAP Settings

  • Incoming server (IMAP): mail.infomaniak.com
  • Port: 993 (SSL/TLS)
  • Outgoing server (SMTP): mail.infomaniak.com
  • Port: 465 (SSL/TLS) or 587 (STARTTLS)
  • Username: your full email address

Most modern clients (Thunderbird, Spark, eM Client) automatically detect these settings through auto-discovery.

Our Recommendation by Profile

For Most Users: Thunderbird

Free, complete, privacy-friendly, and perfectly compatible with Infomaniak. This is our default recommendation.

For Apple Users

Apple Mail – Simple, elegant, integrated. Complement with Spark on iPhone if you want more mobile features.

For Busy Professionals

Spark – The Smart Inbox and snooze are game-changers when you receive 100+ emails a day.

For Former Outlook Users

eM Client – Familiar interface, perpetual license, all the expected features.

For Teams

Spark Teams or Front – Native email collaboration, delegation, internal comments.

Migrating from Outlook: Practical Guide

Step 1: Export Your Outlook Data

If you use Outlook with a local PST file:

  • File → Open & Export → Import/Export
  • Export to a file → Outlook Data File (.pst)
  • Select all folders

Step 2: Import into the New Client

Thunderbird: Use the ImportExportTools NG add-on to import the PST.

eM Client: Direct PST file import via File → Import.

Step 3: Configure Your IMAP Account

If your emails are on an IMAP server (Infomaniak, Exchange...), no need to export: simply configure the same account in your new client and all emails will sync.

Step 4: Migrate Contacts and Calendars

  • Export your contacts in vCard (.vcf) or CSV format
  • Export your calendars in iCalendar (.ics) format
  • Import into your new client or directly into your Infomaniak account

Conclusion

Outlook is not indispensable. Whether you choose Thunderbird for its freedom, Spark for its productivity, or eM Client for its familiarity, you\'ll find an alternative suited to your needs.

Combined with a quality email service like Infomaniak, you get a professional solution that respects your privacy and is independent from American tech giants.

The best time to switch email clients is now.

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Ready to migrate to Infomaniak?

Contact us for a free 15-minute audit. We will analyze your situation and provide you with a personalized quote.

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