Although, there are several Single Window initiatives taking shape all over the world, it is challenging to estimate the number of currently operating systems, due to the differentiated Single Window models adopted and the extent of cross-border operations and functions performed. However, in most cases Customs Administrations have a pivotal role in implementation and operation of SW systems across all six WCO Regions.
The document “Single Window Environment Maturity” make reference to RAMMAP-SWIM Explanatory Note and the SW Compendium Vol.2, Part IX on “Performance management and sustainability”. The aim of the document is to assist Members by providing easy to access information that might serve as an overall self-assessment framework.
WCO has developed Single Window Data Harmonization Guidelines [ru] to provide Single Window environment developers with tools that can be used in order to achieve data harmonization and to develop internationally standardized data sets including the data element names, definitions, the United Nations Trade Data Element Directory (UNTDED) tag and the formats.
To support capacity building efforts, the WCO has developed a Compendium on “Building a Single Window Environment”. The WCO SW Compendium was updated in 2017 and was endorsed by the Council in the same year July session. The new Compendium, which still consists of two Volumes, the Chapters have been re-named as Parts (Part I, Part II, etc.). Each Part focuses on a particular area of the SW Environment, providing comprehensive guidance on building blocks of Single Window implementation. Structural and editorial improvements have been made to some Parts, and four new Parts have been developed.
A supplement Edition to the WCO Single Window Compendium "On How to build a Single Window Environment" [ar] was developed in 2015. The Supplement provides a succinct approach to the Single Window concept, which would be useful to Members and other stakeholders in the implementation/enhancement of Single Window environment. It would serve as a supplementary training package for national and regional Technical Assistance and Capacity Building activities".
The United Nations Centre for Trade Facilitation and Electronic Business (UNCEFACT) has developed Recommendation 33 [ru] on the subject, which is an important piece of work in this area.