ASN.1 extension for Visual Studio

Extending Microsoft Visual Studio family of products with ASN.1 editing

   Install the ASN.1 extension from inside Visual Studio or visit the marketplace:

ASN.1 extension for Microsoft Visual Studio family of products 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. The extension provides:
  • Syntax highlighting and coloring
  • Auto-completion
  • Schema validation and error highlighting
  • Subsection folding and more


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


The extension is available for Visual Studio or Visual Studio Code. You can install it in two ways:

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


  2. Managing extensions from within Visual Studio, searching for ASN1 and installing the one from OSS Nokalva, Inc.

Licensing is available on the extension’s marketplace page.

ASN.1 standards supported

The extension 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).

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