Microsoft Visual Studio Add-On for ASN.1 schemas

  Install the add-on from inside Visual Studio or download it from the marketplace.
ASN1Vsx is a Microsoft Visual Studio extension for ASN.1 schema files that makes it faster and easier to create, modify, and validate your ASN.1 schemas. It combines Visual Studio's powerful code editing capabilities and OSS Nokalva's popular and high-quality ASN.1 software. ASN1Vsx provides:
  • Syntax highlighting and coloring
  • Auto-completion
  • Schema validation and error highlighting
  • Type navigation ("Go to definition" and "Find all references")
  • Subsection folding and more and more


Open an existing ASN.1 schema file or create a new one (the file should have an .asn extension) and start editing.


ASN1Vsx works with Visual Studio 2015 and Visual Studio 2017. You can instal it in two ways:

  1. Downloading from the Visual Studio marketplace, then double-click on it to install it in Visual Studio.


  2. Using the Extension Manager from within Visual Studio. Navigate to the Tools menu, choose Extensions and Updates, choose and expand the Online Gallery node, search for ASN1Vsx to download and install.

ASN.1 standards supported

ASN1Vsx supports the ITU-T 2015 series of ASN.1 specifications and the new JSON encoding rules (certain less popular ASN.1 features may not be supported, contact OSS for details).


Terms of Use

   ASN1Vsx is a free tool in beta stage, we'd appreciate your feedback.