Jeffrey Stedfast
Senior Software Engineer at Microsoft
Pennsylvania, United States
Summary
🤩
Rockstar🎓
Top SchoolJeffrey Stedfast is a senior software engineer with 25 years of experience building robust internet protocols, MIME parsers, and cross-platform UIs for desktop and mobile applications. Now at Microsoft working on Office365 Exchange MIME features, he has a deep background in mail protocols and cryptography, evidenced by long-running open-source projects like MailKit and MimeKit that support S/MIME, DKIM and PGP. His contributions span low-level performance work (optimizing Mono/eglib quicksorts and GLib primitives) to platform integration (Xamarin/.NET iOS/Android tooling and .NET MAUI fixes), showing fluency across systems, tooling and UI layers. He’s a pragmatic maintainer who improves code clarity and reliability—frequently refactoring, fixing subtle bugs, and enhancing cross-platform build and cryptography support. Based in Pennsylvania, he blends systems-level rigor with a practical focus on developer experience and long-term maintainability.
25 years of coding experience
25 years of employment as a software developer
Computer Science, Computer Science at Bucks County Community CollegeAerospace Engineering, Aerospace Engineering at Penn State UniversityComputer Science, Computer Science at The College of New Jersey
English
Stackoverflow
37,067reputation
2.5mreached
1,059answers
3questions
xamarin
top-5%
mime
top-5%
xunit
top-5%
smtp
top-1%
mono
top-1%
encryption
top-5%
Github Skills (90)
xamarin-mac10
c1110
smtps10
xamarin-ios10
security10
glib10
c1710
asp-net10
e-mail10
gmail10
gtk10
excel10
build-automation10
wpf10
encryption10
Programming languages (12)
Github contributions (5)
jstedfast/MailKit
Dec 2013 - Jan 2023
A cross-platform .NET library for IMAP, POP3, and SMTP.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:21 reviews, 2981 commits, 201 PRs in 9 years 3 months
Contributions summary:Jeffrey's contributions primarily focus on the back-end logic and implementation of the MailKit library. They improved socket I/O cancellation, implemented code that handles data responses, incorporated the REPLACE extension into the APIs, and added support for the ANONYMOUS and OAUTHBEARER authentication mechanisms. The user also addressed bugs in the core IMAP and SMTP functionalities.
net-librarypop3c-sharpdkimimap
jstedfast/MimeKit
Oct 2012 - Jan 2023
A .NET MIME creation and parser library with support for S/MIME, PGP, DKIM, TNEF and Unix mbox spools.
Role in this project:Back-end Developer & Cryptography Specialist
Back-end Developer & Cryptography SpecialistContributions:60 reviews, 3537 commits, 233 PRs in 10 years 4 months
Contributions summary:Jeffrey primarily focused on the MimeKit library's cryptography features. They implemented a virtual method GetTimestamp() for DKIM signing and improved documentation for the ArcSigner. They also fixed bugs in the ArcSigner related to body hash calculations and made several unit test additions. The commits include enhancements to the S/MIME signatures by including the certificate chain and adding a new GetRecipients() method.
unixextractionc-sharpdkimspools
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