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NuGet · #1338 most downloaded on NuGet
MimeKit is an Open Source library for creating and parsing MIME messages. It also supports parsing of Unix mbox files. The difference between MimeKit and MimeKitLite is that MimeKitLite lacks support for most cryptography features such as OpenPGP, S/MIME and DKIM. API documentation can be found on the web at http://www.mimekit.net/docs For those that need SMTP, POP3 or IMAP support, check out https://github.com/jstedfast/MailKit
Last release today
19 Sep 2026
Ships fairly regularly
a new release about every 2 months
Nearly every release is documented
notes for 57 of the last 60 stable releases
74 versions withdrawn
withdrawn after publishing
127 years old
155 releases · first in 1900
Mapped the TNEF Sensitivity property to the Sensitivity message header when calling TnefPart.ConvertToMessage().
Optimized SecureMimeCryptographyContext.Supports() and OpenPgpCryptographyContext.Supports() implementations.
One column per quarter.
Fixed a bug in MimeIterator.MoveTo().
Added more bounds checking for parsing mailbox addresses to fix IndexOutOfRangeExceptions given an incomplete address like "Name <". (issue #421)
Make sure messages created from System.Net.Mail.MailMessages have a Date header. (MailKit issue #710)
The default value of the CheckCertificateRevocation property located on the BouncyCastleSecureMimeContext has been changed to false due to privacy con
CheckCertificateRevocation property located on the BouncyCastleSecureMimeContext has been changed
to false due to privacy concerns noted in the Efail document published in May of 2018. Clients that wish
to continue automatic downloads of S/MIME CRLs can manually set the property to true.Allow empty TextBody and HtmlBody properties for BodyBuilder. (issue #391)
IDN encode/decode the local part of mailbox addresses as well. (MailKit issue #649)
Improved the HTML parser logic to better handle a number of edge cases.
Added IDkimPublicKeyLocator.LookupPublicKeyAsync() and MimeMessage.VerifyAsync() to support asynchronous DNS lookups of DKIM public keys.
Fixed a buffering bug in MimeParser's header parser. (issue #358)
Added async support for writing MimeMessage, MimeEntity, HeaderList and ContentObject.
Added CanSign() and CanEncrypt() methods to CryptographyContext for checking whether or not a mailbox can be used for signing or be encrypted to. (iss
Allow importing of known PGP keys (needed when re-importing keys after signing them). (issue #315)
Fixed a bug in the MailMessage to MimeMessage conversion which corrupted the Subject string. (issue #306)
Fixed TextToHtml and FlowedToHtml's OutputHtmlFragment property to work.
Added new ParserOptions option to allow local-only mailbox addresses (e.g. no @domain).
Added International Domain Name support for email addresses.
Added new DKIM MimeMessage.Sign() methods that take an IList<string> of header field names to sign.
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databases such as Postgres do not). (issue #286)Fixed the Content-Type and Content-Disposition parameter parser to remove trailing lwsp from unquoted parameter values. (issue #278)
Fixed OpenPgpContext.Verify() to throw FormatException if no data packets found.
Improved parsing of malformed mailbox addresses.
Fixed QuotedPrintableDecoder to handle soft breaks that fall on a buffer boundary.
Added support for .NET Core 1.0
Fixed parsing bugs in MessageDeliveryStatus.StatusGroups. (issue #253)
Modified MimeMessage .ctor to not add an empty To: header by default. (issue #241)
Modified ParamaterList.TryParse() to handle quoted rfc2231-encoded param values. (issue #239)
Added a new SecureMimeContext.Verify() overload that returns the extracted content stream.
Added a MultipartReport class for multipart/report.
Fixed serialization of mime parts with empty content. (issue #221)
Handle illegal Content-Id headers that do not enclose their values in <>'s. (issue #215)
Removed unimplemented TNEF APIs.
Fixed DkimRelaxedBodyFilter to properly handle CRLF split across buffers.
Fixed the Date parser to catch exceptions thrown by the DateTimeOffset .ctor if any of the fields are out of range.
Fixed DKIM-Signature signing logic to use a UTC-based timestamp value rather than a timestamp based on the local-time. (issue #180)
Modified Base64Encoder's .ctor to allow specifying a maxLineLength.
Prevent infinite loop when flushing CharsetFilter when there is no input data left.
Fixed an IndexOutOfRangeException bug in the TextToHTML converter logic. (issue #165)
Added public Stream property to IContentObject.
Fixed WriteTo(string fileName) methods to overwrite the existing file. (issue #154)
Added a new MessageDeliveryStatus MimePart subclass to make message/delivery-status MIME parts easier to deal with.
Fixed encoding GroupAddress with multiple mailbox addresses.
Fixed a bug in the HTML tokenizer to handle some weird HTML created by Outlook 15.0.
Changed BodyParts and Attachments to be IEnumerable<MimeEntity> - WARNING! This is an API change! (issue #148)
Added support for generating and verifying DKIM-Signature headers.
Fixed TextToFlowed logic that stripped trailing spaces.
Added a MultipartAlternative class which adds some useful convenience methods and properties for use with the multipart/alternative mime-type.
Added a Format property to ContentType.
Force the use of the rfc2047 "B" encoding for ISO-2022-JP. (issue #139)
Fixed MimeMessage.WriteTo() to be thread-safe. (issue #138)
Added a convenience CmsSigner .ctor that takes an X509Certificate2 argument.
Added a work-around for a bug in Thunderbird's multipart/related implementation. (issue #124)
Modified InternetAddressList.Equals() to return true if the lists contain the same addresses even if they are in different orders. (issue #118)
Added the ContentDisposition.FormData string constant.
Ignore semi-colons in Content-Transfer-Encoding headers to work around broken mailers.
Added a new MessageDispositionNotification MimePart subclass to represent message/disposition-notification parts.
Modified the parser to accept Message-Id values without a domain (i.e. " ").
Fixed TnefPropertyReader.GetEmbeddedMessageReader() to skip the Guid.
Vastly improved MS-TNEF support. In addition to being fixed to properly extract the AttachData property of an Attachment attribute, more metadata is c
Note: If you are not yet ready to port your iOS application to the Unified API, you will need to stick with the 1.0.5 release. The Classic MonoTouch API is no longer supported.
Fixed out-of-memory error when encoding some long non-ASCII parameter values in Content-Type and Content-Disposition headers.
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