A fake SMTP server for development.
Publisher’s description
What is smtp4dev?
smtp4dev by Robert N Wood is open-source Windows software. It is written in C#.
Installation and requirements
The publisher provides Portable installers for 64-bit and ARM64 Windows. It runs without installation (portable).
Updates and version history
The current version is 3.15.0, released on March 3, 2026. The version history goes back to September 10, 2025: 5 releases, all linked to the official files.
Popularity and file types
The source code on GitHub (rnwood/smtp4dev) has 4,009 stars.
Project description on GitHub: “smtp4dev - the fake smtp email server for development and testing”
Pros / Cons
Pros
- Open source: the code can be inspected and built by anyone
- Native ARM64 build for Windows on Arm
- Portable: runs without installation
In short: smtp4dev is an open-source Windows tool for 64-bit and ARM64 PCs.
Is smtp4dev safe to download?
- The file is served by github.com, the publisher’s own domain
- The download link uses HTTPS
- A SHA256 hash is published, so you can verify the file:
9ED061316772445D54F09B4BD69B97DC79E830312C8F32A8C1717C24FD7068DC· Open the VirusTotal report for this hash - The link has not been checked yet
- The source code is public
- ExeAtlas does not host, wrap or modify installers
Related guide: How to check a file’s SHA256 hash on Windows
Security practices (OpenSSF Scorecard)
Automated checks of the rnwood/smtp4dev repository on GitHub by the Open Source Security Foundation, last run on October 19, 2026.
- Actively maintained10
- Code review10
- No dangerous workflows10
- No binaries in the repository10
- Licence declared10
- Static code analysis9
- Restricted token permissions0
- OpenSSF Best Practices badge0
- Security policy0
- Fuzzing0
- Pinned dependencies0
- Signed releases0
The score rates how the project is developed and released, not whether the program is safe to install. scorecard.dev
Recent versions
All 5 versions ›| Version | Date | Size | Files |
|---|---|---|---|
| 3.15.0Latest | March 3, 2026 | — | 64-bit ZIPARM64 ZIP |
| 3.10.3 | September 23, 2025 | — | ARM64 ZIP64-bit ZIP |
| 3.10.2 | September 22, 2025 | — | ARM64 ZIP64-bit ZIP |
| 3.10.1 | September 14, 2025 | — | 64-bit ZIPARM64 ZIP |
| 3.9.0 | September 10, 2025 | — | ARM64 ZIP64-bit ZIP |
Install from the command line
Silent install ›winget install --id Rnwood.Smtp4dev -eRelated guide: How to use winget: install and update apps
Information
- Publisher
- Robert N Wood
- Licence
- BSD-3-Clause
- Price
- Free
- Source code
- github.com/rnwood/smtp4dev
- Written in
- C#
- Requires
- Windows 11 / 10
- Architecture
- 64-bit, ARM64
- Installer
- Portable
- Version
- 3.15.0
- Released
- March 3, 2026
- Added to the catalogue
- September 10, 2025
- Versions listed
- 5
- GitHub stars
- 4,009
- GitHub forks
- 425
- Website
- github.com
- winget ID
- Rnwood.Smtp4dev
Ratings and reviews
No reviews yet. Be the first to rate it.
Frequently asked questions
Is smtp4dev free?
Yes. smtp4dev is open-source software under the BSD-3-Clause licence.
Is smtp4dev safe to download?
The download comes from github.com, which belongs to the publisher; ExeAtlas does not host or change the file. Compare its SHA256 hash with the one shown here, or open the VirusTotal report for that hash.
How do I install smtp4dev with winget?
Open PowerShell or Windows Terminal and run the winget command shown on this page. winget downloads the official installer and checks its SHA256 hash before running it.
Does smtp4dev run on ARM (Windows on Arm)?
Yes, there is a native ARM64 installer.
Where can I download an older version of smtp4dev?
The versions page lists all 5 versions with links to their official installer files, back to September 10, 2025.
Can I use smtp4dev without administrator rights?
Yes, it is portable: unpack and run it.
