Email client
An email client (alternatively spelled e-mail client; commonly known as mail client; more formally known as mail user agent or MUA; hereinafter, the Client) is any digital construct that an end-user utilizes to compose, access, and/or manage his or her emails.
The Client can also refer to mail client software. More broadly, email software may refer to all the software utilized for the Clients, mail servers, or mail exchangers.
Contents
Functions
Communication
- With regard to:
- Outgoing messages, the Clients may be designed to:
- Accept requests from end-users to compose new messages.
- Analyze requests looking for their inconsistencies and/or missing data.
- Offer end-users to correct inconsistencies and/or add the missing data.
- Transfer messages to mail servers.
- Stored messages, the Clients may be designed to:
- Accept requests from end-users to manage -- delete, arrange, label, classify -- stored messages.
- Offer end-users to confirm those changes that are setup as critical.
- Execute the requests -- delete, arrange, label, classify -- stored messages.
- Incoming messages, the Clients may be designed to:
- Accept messages from mail servers.
- Analyze messages looking for their inconsistencies and/or missing data.
- Add information about the found inconsistencies and/or missing data to the messages. This information may further be used by mail clients to combat spam.
- Display messages to end-users.
- Outgoing messages, the Clients may be designed to:
- On the one side, the Clients receive requests from and display the data to end-users. On the other side, the Clients communicate with mail servers in order to receive emails from and/or send emails to.
Mailbox management
Message composition
Encryption
Hosting
There are two major models of locating the Clients:
- On-premises: end-users may install the Clients on their devices; a common example would be an app running on one's cell phone. The POP3 protocol is commonly used for sending one's emails to and/or receiving from mail servers.
- Online: end-users may access the Clients that are hosted online, often, next to a mail server. The IMAP protocol is commonly used for accessing and/or managing one's emails online.
Software
General comparison
General comparison of the popular Clients Category Features Evolution Outlook RoundCube Thunderbird Zimbra Trivia Ownership OSS Proprietary OSS OSS OSS Developer Community Microsoft Community Foundation Corporation License GPL Unknown GPL MPL YPL-like UI GUI (GTK) GUI GUI GUI (XUL) GUI Latest release 3.32.2 2019(16) 1.2.5 60.7.2 8.6.0 Date 05/08/2019 09/24/2018 04/28/2017 06/20/2019 12/15/2014 Introduction 2000 1997 2006 2003 2005 OS Windows No Yes Cross-platform Cross-platform Cross-platform macOS No Yes Linux UNIX-like No BSD No Unix No Category Features Evolution Outlook RoundCube Thunderbird Zimbra
Communication protocols
Communication protocols supported by the popular Clients Category Features Evolution Outlook RoundCube Thunderbird Zimbra IMAP IMAP4 Yes Yes Yes Yes Yes POP3 Fetch all messages Yes Yes Yes Yes Yes Selected by filter No No No No No Selected by user Yes No No No No Communication protocols other than POP3 and IMAP SMTP Yes Yes Yes Yes Yes NNTP Yes No No Yes No EWS Plug-in Yes Unknown Extensible Unknown IPv6 Unknown Yes Unknown Yes Unknown MAPI Plug-in Yes Unknown Unknown Unknown Category Features Evolution Outlook RoundCube Thunderbird Zimbra
Integration protocols
Integration protocols supported by the popular Clients Category Features Evolution Outlook RoundCube Thunderbird Zimbra RSS 0.91 Feeds No Unknown Unknown No Unknown 1.0 Feeds No Unknown Unknown No Unknown 2.0 Feeds No Yes Unknown Yes Yes Integration protocols other than RSS IMSP No Yes Unknown Yes Yes ACAP No Yes Unknown Yes Yes ATOM Feeds No Yes Unknown Yes Yes iCalendar Yes Yes Unknown Yes Yes MAPI/RPC Yes Yes Unknown Yes Unknown CalDAV Yes No Unknown Yes Unknown CardDAV Yes No Plug-in Yes Unknown Category Features Evolution Outlook RoundCube Thunderbird Zimbra
Access
Access and security in the popular Clients Category Features Evolution Outlook RoundCube Thunderbird Zimbra LDAP v2 Yes Yes Yes Partial Yes v3 Yes Unknown Yes Partial Yes Regular authentication Login Yes Yes Yes Yes Yes Plain Yes No Yes Yes Yes CRAM-HMAC MD5 Yes No Yes Yes Yes SHA1 No No Yes No Unknown RIPEMD No No Unknown No Unknown MD5 APOP Yes No Yes Yes Yes DIGEST-MD5 Yes No Yes No Unknown Other authentication MSN (NTLM) browser login Yes Yes Unknown Yes Unknown Compuserve (RPA) No No Unknown No Unknown Hardware token PKCS#11 No No Yes Yes Yes Biometric No No Unknown No Unknown SMTP Auth Yes Yes Yes Yes Yes X.509 client certificate No No Unknown Yes Unknown OAuth Unknown Unknown Unknown Yes Unknown Category Features Evolution Outlook RoundCube Thunderbird Zimbra
Security
Access and security in the popular Clients Category Features Evolution Outlook RoundCube Thunderbird Zimbra SSL/TLS support Secure POP3 SSL/TSL SSL SSL/TSL SSL/TSL SSL/TSL Secure IMAP4 SSL/TSL SSL/TSL SSL/TSL SSL/TSL SSL/TSL Secure SMTP SSL/TSL SSL/TSL SSL/TSL SSL/TSL SSL/TSL Secure NNTP SSL/TSL Unknown No SSL/TSL SSL/TSL Secure LDAP SSL/TSL Unknown SSL/TSL SSL SSL/TSL SNI Unknown Unknown Unknown Yes Unknown OCSP No Unknown Unknown Yes Unknown CRL No Unknown Unknown Yes Unknown PGP support inline Yes No Unknown Yes Unknown PGP/MIME or OpenPGP Yes No Yes Yes No Category Features Evolution Outlook RoundCube Thunderbird Zimbra
Message management
Integration protocols supported by the popular Clients Category Features Evolution Outlook RoundCube Thunderbird Zimbra Filtering Local junk Yes Yes Yes Yes Yes Server-side junk Unknown Yes Yes Yes Yes Phishing No Yes Depends on antivirus Yes Depends on antivirus S/MIME support protocol Yes Yes Yes Yes Unknown OCSP Unknown Unknown Unknown Yes Unknown CRL Unknown Yes Unknown Unknown Unknown Certificates on tokens, smartcards support Unknown Yes Unknown Yes Unknown Appearance HTML email Yes Yes Yes Yes Yes UTF-8 support Yes Yes Yes Yes Yes Image blocking Yes Yes Yes Yes Yes Thread view Yes Yes Yes Yes Yes Conversation view No Yes Unknown Yes Unknown Message (general) Bi-directional text support Postpone/scheduled message sending Label messages with colors with flag antidelete add note Reformat received messages edit headers (e.g., Subject) forced recode Composing messages Spell checking Signatures Bottom-posts replies Native images preview jpeg gif bmp png others Native documents preview txt pdf doc xls odt ods others Database Message file format Encrypted database Virtual folders Scheduled backup New mail notification ticker tray icon tooltip sound Folders Customizable interface Customizable keybindings Fragmented messages Database search with regular expressions support Indexed search Search folders IMAP Search IDLE Message templates new reply forward read confirmation save print Individual for Support in message templates scripts, programming languages JavaScript VBScript PHP Scripts Python Regular expressions Java Other (specify)