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ICANN Org Increases Functionality of Label Generation Rules Toolset

22 November 2023

The ICANN organization (org) has updated the Label Generation Rules (LGR) Toolset, providing functionality for checking conformance with IDNA2008 in addition to existing functions for validating a label, generating variant labels, managing LGRs, and reviewing Internationalized Domain Name (IDN) Tables.

The LGR Toolset assists end users in validating IDN labels and determining their variant labels and brings consistency and transparency to the IDN Table review process for registry operators.

To use the LGR Toolset, please visit the LGR Toolset webpage. The toolset includes three modes:

Validate Label(s) Mode: In this mode, the tool validates the label(s) and generates the variant label(s) according to the selected reference data. The available reference data are Reference LGRs for the Second Level and Root Zone LGRs. The user manual for this mode is available here.

Advanced LGR Mode: Users can create, view, and manage LGRs in this mode. The tool can merge multiple LGRs and determine cross-script variants of the labels using a merged LGR. Users can upload a list of labels to validate and generate variant labels based on the user's developed LGR. The user manual for this mode is available here.

Review IDN Table(s) Mode: The tool compares IDN tables with the Reference LGRs for the second level, or with Root Zone Label Generation Rules (RZ-LGR) where the Reference LGRs are not yet available. Now the tool also provides the option to compare the IDN table(s) against the explicit requirements in the IDNA2008 standard (RFC5890, RFC5891, RFC5892, and RFC5893). The user manual for this mode is available here.

The tool has a Label Form function, which generates the A-label, U-label, and code points of the input label(s) if they comply with the IDNA2008 standard.

The source code for the LGR Toolset on GitHub is also available on the LGR Toolset webpage. Feedback and user questions can be directed to ICANN Global Support at globalsupport@icann.org.


ICANN's mission is to help ensure a stable, secure, and unified global Internet. To reach another person on the Internet, you need to type an address – a name or a number – into your computer or other device. That address must be unique so computers know where to find each other. ICANN helps coordinate and support these unique identifiers across the world. ICANN was formed in 1998 as a nonprofit public benefit corporation with a community of participants from all over the world.