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IMAP Client library using C#

, 20 Sep 2012 MPL
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IMAPLibrary supports the basic IMAP protocol functions to fetch messages from the mailbox.


The Internet Message Access Protocol (IMAP) allows a client to access and manipulate electronic mail messages on a server. It includes operations for creating, deleting, and renaming mailboxes; checking for new messages; permanently removing messages; setting and clearing flags; [RFC-822] and [MIME-IMB] parsing; searching; and selective fetching of message attributes, texts, and portions thereof. For more information: here.

I have written an IMAP client library which allows basic functionalities like login, select/examine folder, search messages, fetch message (Header, Body), get storage quota, and logout.

This is my first application developed in C#, so don't expect too much in terms of efficiency. It demonstrates the use of sockets, XML writer, and user defined exception handling. Please feel free to modify and use this code.

The attached zip file contains three directories.

IMAP Library: It contains three source files.

  • ImapBase.cs: contains the IMAP commands related to string, and socket related functionality.
  • ImapException.cs: defines the user defined IMAP related error messages.
  • Imap.cs: IMAP client library functions. It has the following public functions:
    • Login: Login to IMAP server. It requires IMAP hostname, port, username, and password.
    • Logout: Logout and close the socket.
    • SelectFolder: It selects the folder. It requires folder name as parameter.
    • ExamineFolder: It is similar to SelectFolder, but it does examine.
    • GetQuota: Get the quota of the mailbox.
    • SearchMessage: You can search the messages. It will return the UID of messages. E.g., From rjoshi.
    • FetchMessage: It retrieves the complete message with attachments and writes into an XML file. The XML file will be generated in your current directory with file name as <MessageUID>.xml. You need to pass the XmlTextWriter object, message UID, and flag to fetch body.
    • FetchPartBody: Fetch the body for a specific part. It requires message UID, part number as parameter.
    • FetchPartHeader: Fetch the header of message.

Documentation: HTML Documentation for IMAP Library generated using Visual Studio .NET.

IMAP Library test program: The IMAP test program allows users to test the following functionalities.

  • Login
  • Select/Examine folder
  • Search
  • Fetch Message
  • Get Quota
  • Logout
  • Delete Message
  • Mark Message UnRead 
  • Move Message


Update: Added support for

  1. SSL Connection and verified with gmail
  2. Copy Message
  3. Move Message
  4. Delete Message 
  5. Mark Message Unread  
Please don't forget to Vote if you like this library !!


This article, along with any associated source code and files, is licensed under The Mozilla Public License 1.1 (MPL 1.1)


About the Author

Rohit Joshi
Software Developer
United States United States
Rohit Joshi is a software engineer working for a telecom company in USA. He has development expirience using C, C++ ,C#, VoiceXML, ASR, IMAP, LDAP, HTTP, SIP, H323 on unix/linux and platforms.

Comments and Discussions

QuestionHow do you retreive attachments? PinmemberDan Guzman14-Sep-11 13:36 
AnswerRe: How do you retreive attachments? PinmemberRohit Joshi4-Apr-12 5:00 
GeneralRe: How do you retreive attachments? Pinmembervishal.suthar21-Jul-12 4:01 
GeneralCannot connect to Gmail IMAP on Port 993 PinmemberKmistry16-Jun-11 12:09 
GeneralRe: Cannot connect to Gmail IMAP on Port 993 PinmemberSyed Majid Ali Gardezi10-Oct-11 2:35 
QuestionGetting Email size PinmemberRamaNeni13-May-11 1:17 
AnswerRe: Getting Email size PinmemberRohit Joshi7-Jun-12 8:54 
GeneralError: Failure connecting to the IMAP server. Pinmembernyeinchan.ucsm4-May-11 18:26 
Hi All,
I downloaded IMAP Client library and trying to test with Host: , User:...., Password:.... . But I got an error like "Error: Failure connecting to the IMAP server.". I trying to connect with port 993, but I got the same error. I can't login to IMAP server.Please give me any advice.
Thanks and Regards
GeneralRe: Error: Failure connecting to the IMAP server. PinmemberAnushaRose12-Apr-12 1:08 
GeneralRe: Error: Failure connecting to the IMAP server. PinmemberRohit Joshi6-Jun-12 11:09 
GeneralCommand "UID SEARCH FROM" in Exchange 2010 PinmemberMember 769955225-Feb-11 6:21 
GeneralDid SSL ever get added PinmemberScott W Bowyer24-Feb-11 13:27 
GeneralRe: Did SSL ever get added PinmemberDhaidh30-May-12 6:52 
GeneralRe: Did SSL ever get added PinmemberRohit Joshi6-Jun-12 11:36 
GeneralRe: Did SSL ever get added PinmemberRohit Joshi6-Jun-12 11:37 
GeneralNewbie Q, i dont understand something PinmemberGothrek21-Feb-11 2:12 
GeneralRe: Newbie Q, i dont understand something PinmemberRohit Joshi4-Apr-12 5:02 
GeneralRe: Newbie Q, i dont understand something PinmemberRohit Joshi6-Jun-12 11:10 
QuestionGetting Wrong Pinmemberjymitra29-Dec-10 0:32 
AnswerRe: Getting Wrong PinmemberRohit Joshi21-Jan-11 10:48 
GeneralRe: Getting Wrong Pinmemberjymitra21-Jan-11 21:14 
QuestionMARKING LABELS [modified] PinmemberVaishalimehre13-Oct-10 13:40 
QuestionHelp about store flag "UNSEEN" Pinmemberjymitra11-Oct-10 22:16 
AnswerRe: Help about store flag "UNSEEN" PinmemberRohit Joshi12-Oct-10 16:34 
GeneralRe: Help about store flag "UNSEEN" Pinmemberjymitra12-Oct-10 21:21 

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