kkkgo/vlmcsd
Free🔑Portable open-source KMS Emulator in C
FreeFree tier
About kkkgo/vlmcsd
vlmcsd is a portable open-source KMS emulator written in C. It serves as a replacement for Microsoft's KMS server for activating volume license editions of Windows and Office. The tool includes a KMS test client (vlmcs) for debugging and charging genuine KMS servers. Designed to run on always-on devices such as routers or NAS boxes, it supports a wide range of operating systems (Linux, Windows, macOS, FreeBSD, etc.) and CPU architectures (x86, ARM, MIPS, PowerPC, etc.). vlmcsd is intended to help users who have lost activation of their legally-owned licenses due to hardware changes, and explicitly states it is not a crack or one-click activation tool.
Key Features
Portable open-source KMS emulator written in C
Supports 202 Microsoft products (Windows Server, Windows 10/11, Office, etc.)
Includes vlmcs KMS test client for debugging and charging servers
Cross-platform: Linux, Windows, macOS, FreeBSD, OpenBSD, NetBSD, Solaris, iOS, Android, and more
Multiple CPU architectures: x86, ARM, MIPS, PowerPC, SPARC, s390
Designed for always-on devices like routers and NAS boxes
Fully Microsoft KMS server compatible
Pros & Cons
Pros
- Free and open source
- Portable and cross-platform with extensive OS and CPU support
- Supports a wide range of Microsoft volume license products (202 products)
- Includes a test client for verification and debugging
- Active community on GitHub (1.1k stars, 310 forks)
- Well-documented with man pages and plain text documentation
Cons
- Requires technical knowledge to set up and configure
- Not a one-click activation tool; manual setup needed
- May be used for unauthorized activation (though intended for legal use)
- No graphical user interface; command-line only
- Limited to volume license editions (not retail licenses)
Best For
Activating volume license editions of Windows and Office on legally-owned machines after hardware changesSetting up a local KMS server on a router or NAS for network activationTesting and debugging KMS server implementations with the bundled vlmcs clientReplacing a Microsoft KMS server in enterprise environments
FAQ
What is vlmcsd?
vlmcsd is a portable open-source KMS emulator written in C. It serves as a replacement for Microsoft's KMS server for activating volume license editions of Windows and Office. It includes a KMS test client (vlmcs) for debugging and charging genuine KMS servers.
What products does it support?
vlmcsd supports 202 Microsoft products, including Windows Server 2019/2022, Windows 10/11 (Enterprise, Professional, Education, etc.), Windows 7, Office, Project, Visio, and more. A full list is available in the repository.
Is vlmcsd legal?
The tool is intended to help users who have legally-owned volume licenses but have lost activation due to hardware changes. The developers explicitly state it is not a crack or one-click activation tool. Use must comply with Microsoft's licensing terms.
What operating systems does vlmcsd run on?
It supports Linux (including uclibc, musl, Android), FreeBSD, OpenBSD, NetBSD, DragonflyBSD, Solaris, Open Indiana, Dyson, Minix, Darwin (macOS, iOS), Windows (including Cygwin, WSL), and more.