# jstedfast/MimeKit

A .NET MIME creation and parser library with support for S/MIME, PGP, DKIM, TNEF and Unix mbox spools.

Repository: https://github.com/jstedfast/MimeKit
Canonical: https://ross.abutalabs.com/products/mimekit
Homepage: http://www.mimekit.net
Language: C#
License: MIT
License Family: permissive
Topics: c-sharp, email, mime, parser, mime-parser, mbox, pgp, smime, dkim, tnef
Last push: 2026-08-15T21:05:44+00:00

## Health v2 (maintenance only)
Score: 76/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 97, release rhythm 35, longevity 100
- inputs: {"age_days": 5057, "days_push": 18, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2000, forks 388 (observed 2026-08-28T04:06:04.315917+00:00)

## What it is
MimeKit is a C#/.NET library for creating and parsing MIME email messages, with support for S/MIME, OpenPGP, DKIM, ARC, TNEF, and Unix mbox spools. It is designed for high performance, capable of parsing gigabytes of mail in seconds, and runs across Windows, Linux, macOS, iOS, and Android.

## Use cases
- parse email messages from streams or files in .NET
- parse a Unix mbox spool file
- create MIME-compliant email messages programmatically
- encrypt, decrypt, sign, and verify S/MIME messages
- sign and verify OpenPGP email messages
- verify DKIM and ARC signatures on incoming mail
- build cross-platform mobile mail apps with Xamarin

## When to choose
- you need a fast, robust MIME parser for .NET that handles arbitrary character encodings
- you need S/MIME, OpenPGP, DKIM, or ARC support in email processing
- you need to parse mbox spools or large volumes of mail quickly
- you want a free, MIT-licensed library usable commercially across desktop and mobile platforms

## When to avoid
- you need SMTP/IMAP/POP3 client functionality - use its companion library MailKit instead
- you are not on a .NET platform
- you need a lightweight non-.NET MIME parser in C, Python, or another language

## Facets
- artifact type: library
- maturity: stable
- function: parser, serialization, cryptography, email
- domain: email, security, developer-tools, parsers
- platform: dotnet, cross-platform, windows
- tags: mime, smime, openpgp, dkim, arc, mbox, tnef, mail-processing, nuget, linux, macos, android, ios

## Member repositories
- jstedfast/MimeKit (main) score 76

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:04.315917+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:02:07.881103+00:00, confidence not recorded.
  - readme: https://github.com/jstedfast/MimeKit (fetched 2026-08-28T04:06:04.315917+00:00, sha 59d558658b43)
  - homepage: http://www.mimekit.net (fetched 2026-08-29T10:41:50.561532+00:00, sha d0244e6a4814)
  - site_page: https://mimekit.net/docs (fetched 2026-08-29T10:41:50.570996+00:00, sha a1b0716a5a55)
  - site_page: https://mimekit.net/docs/html/Parsing-Messages.htm (fetched 2026-08-29T10:41:50.572880+00:00, sha e0ca0691ddc3)
  - site_page: https://mimekit.net/docs/html/Working-With-SMime.htm (fetched 2026-08-29T10:41:50.575176+00:00, sha 403299079b12)
- Data as of 2026-08-30T08:39:29.467469+00:00.