Open Source Horde Alternatives

The best open source alternative to Horde is Roundcube. If that doesn't suit you, our users have ranked more than 25 alternatives to Horde and 19 is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Horde are Rainloop, mailcow: dockerized, Mailpile and Zimbra Collaboration Suite.

Horde alternatives are mainly WebMail Providers but may also be Email Clients or Mail Servers. Filter by these if you want a narrower list of alternatives or looking for a specific functionality of Horde.

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Horde

Free • Open Source
WebMail Provider

Online
Self-Hosted

Horde Groupware is a free, enterprise ready, browser based collaboration suite. Users can manage and share calendars,...

Learn more about Horde

Roundcube
Is this a good alternative?
Yes
No
Free • Open Source
WebMail Provider
Email Client
Mail Server
Self-Hosted
PHP
Cloudron
29 alternatives to Roundcube
Roundcube webmail is a browser-based multilingual IMAP client with an application-like user interface. It provides full functionality you expect from an e-mail client, including MIME support, address book, folder manipulation, message searching and spell checking.
Suggest and vote on features
Roundcube Features
1. PGP EncryptionRoundcube supports PGP, an encryption system used for sending encrypted emails and files.
Hostable
IMAP Support
Rainloop
Is this a good alternative?
Yes
No
Free • Open Source
Email Client
Mail Server
Online
Self-Hosted
Nextcloud
JavaScript
PHP
Cloudron
12 alternatives to Rainloop
Simple, modern & fast web-based email client. Modest system requirements, decent performance, simple installation and upgrade, no database required. All these make RainLoop Webmail a perfect choice for your email solution.
Suggest and vote on features
Rainloop Features
1. Ad-freeRainloop doesn't contain any form of external advertising.
2. Multiple Account supportRainloop support multiple accounts without the need to logout and login
Encrypted Email
Dockerized
IMAP Support
mailcow: dockerized
Is this a good alternative?
Yes
No
Free • Open Source
Mail Server
Linux
Self-Hosted
18 alternatives to mailcow: dockerized
mailcow is a mail server suite based on Dovecot, Postfix, SOGo, Rspamd and other open source software, that provides a modern Web UI for administration.
Suggest and vote on features
mailcow: dockerized Features
Self hosted mail
Support for Docker
ActiveSync
Dockerized
Modular System
Mailpile
Is this a good alternative?
Yes
No
Free • Open Source
Email Client
WebMail Provider
Linux
Online
Self-Hosted
OpenPGP
59 alternatives to Mailpile
Mailpile is a modern, fast web-mail client with user-friendly encryption and privacy features. The development of Mailpile is funded by a large community of backers and all code related to the project is and will be released under an OSI approved Free Software license.
Suggest and vote on features
Mailpile Features
1. OpenPGPMailpile supports OpenPGP, a standard of PGP encryption that is open-source for public use.
Web-Based
Encrypted Email
IMAP Support
POP3 Support
Discontinued
1.0.0 Release Candidate 6 from 2019 is the last version on GitHub (https://github.com/mailpile/Mailpile/releases). Possibly the development has been stopped.
Zimbra Collaboration Suite
Is this a good alternative?
Yes
No
Freemium • Open Source
Mail Server
Calendar App
Team Collaboration Tool
Linux
Online
Self-Hosted
43 alternatives to Zimbra Collaboration Suite
Zimbra Collaboration is an open, secure collaboration tool for email, calendaring, tasks and more. With the most innovative web application available today, Zimbra boosts the productivity of users on any desktop and dramatically reduces TCO compared to legacy platform vendors.
Suggest and vote on features
Zimbra Collaboration Suite Features
1. Real time collaborationMultiple users can work together in Zimbra Collaboration Suite simultaneously.
ActiveSync
Active Directory integration
Zimbra Collaboration Suite vs Horde
pros, cons and recent comments
sondrak
Similar scope of groupware functionality, including calendar, tasks, etc.
Positive comment• ago

0
SOGo
Is this a good alternative?
Yes
No
Freemium • Open Source
WebMail Provider
Linux
Online
Thunderbird
Cloudron
64 alternatives to SOGo
SOGo is groupware server with a focus on scalability and open standards.

SOGo provides a rich AJAX-based Web interface and supports multiple native clients through the use of standard protocols such as CalDAV, CardDAV and GroupDAV.Share your calendars, address books and mails in.
Suggest and vote on features
SOGo Features
Support for Multiple Users
Scheduling
CalDAV Support
CardDAV Support
Squirrelmail
Is this a good alternative?
Yes
No
Free • Open Source
WebMail Provider
Self-Hosted
PHP
17 alternatives to Squirrelmail
SquirrelMail is a standards-based webmail package written in PHP. It includes built-in pure PHP support for the IMAP and SMTP protocols, and all pages render in pure HTML 4.0 (with no JavaScript required) for maximum compatibility across browsers.
Suggest and vote on features
Squirrelmail Features
SMTP Support
IMAP Support
Exchange
On-premises software
SnappyMail
Is this a good alternative?
Yes
No
Free • Open Source
Email Client
Self-Hosted
Web Browser
12 alternatives to SnappyMail
The drastically upgraded & secured fork of RainLoop Webmail Community edition.
Suggest and vote on features
SnappyMail Features
1. LightweightSnappyMail consumes less device resources compared to similar apps.
2. Ad-freeSnappyMail doesn't contain any form of external advertising.
Mobile friendly
iRedMail
Is this a good alternative?
Yes
No
Freemium • Open Source
Mail Server
Linux
BSD
Self-Hosted
69 alternatives to iRedMail
A fully fledged, free email server solution, an open source project (GPL v2).

Use official binary packages from Linux/BSD distributions, with both i386 and x86_64 support.

Easy, fast deployment in LESS THAN 1 MINUTE. View YouTube Video to check how easy it is.

Works on both no.

iRedMail has no features, suggest some!
Isotope Mail Client
Is this a good alternative?
Yes
No
Free • Open Source
WebMail Provider
Email Client
Mail Server
Mac
Windows
Linux
Online
Self-Hosted
Kubernetes
Docker
OpenShift
11 alternatives to Isotope Mail Client
Microservice based webmail client built with ReactJS and Spring.

Minimalistic webmail client which currently has the main features of any other mail client (read mail, compose mail, organize mail folders...).
Suggest and vote on features
Isotope Mail Client Features
1. AutocompletionIsotope Mail Client can predict and complete the rest of a word or phrase you're typing.
No database needed
Drag and Drop
Support for Docker
Web-Based
Rich text editing
Dockerized
Isotope Mail Client vs Horde
Almost everyone thinks Isotope Mail Client is a great alternative to Horde.