vies-dotnet-api

August 16, 2026 ยท View on GitHub

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European (EU) VIES API VAT validation for dotnet based on the most current information from the official source

The vies-dotnet-api enables users to verify the validity of a specified VAT identification number for intra-Community goods or services transactions

Installing

The fastest way of getting started using Vies api is to install the NuGet package.

Package Manager:

Install-Package vies-dotnet-api -Version 4.0.0

.NET CLI:

dotnet add package vies-dotnet-api --version 4.0.0

Package Reference

<PackageReference Include="vies-dotnet-api" Version="4.0.0" />

Usage

Checking a VAT number using the vies-dotnet-api

Checking if an EU VAT number is valid

 var result = ViesManager.IsValid("RO123456789");

or

 var result = ViesManager.IsValid("RO","123456789");

Checking if an EU VAT number is active

var viesManager = new ViesManager();

var result = await viesManager.IsActiveAsync("RO123456789");

or

var result = await viesManager.IsActiveAsync("RO","123456789");

Selecting the VIES endpoint

Starting with v4, ViesManager calls the VIES REST (JSON) API by default. The legacy SOAP endpoint remains available by passing ViesApiEndpoint.Soap:

var viesManager = new ViesManager(ViesApiEndpoint.Soap);

The existing examples above work unchanged and use the REST endpoint by default.

Clarification

Since January 1, 2021 the UK is no longer a member of the European Union and as a result, the VIES service provided by the European Commission no longer validates VAT ID's for the UK.

Checking GB VAT number

...
var validationResult = await viesManager.IsActiveAsync("GB434031494");

will return the following message:

Great Britain(GB) is no longer supported by VIES services provided by EC since 2021-01-01 because of Brexit.


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License

GitHub license

The API is released under the Apache 2 open-source license. You can use it for both personal and commercial purposes, build upon it and modify it.

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