@deckyard/vies

EU VAT number validation through VIES, the European Commission's VAT Information Exchange System, for Jennifer programs: check a customer's VAT number before invoicing without VAT (reverse charge), with the trader's name and address, and get a consultation number as proof of the check. Numbers are normalised and checked against their country's syntax offline; VIES's faults keep "the member state is down, try later" apart from "the number is wrong".

Documentation

Install

jvc add @deckyard/vies

This vendors the deck to vendor/<scope>/vies/. Without jvc, unpack the src/ subtree of a release archive (<scope>-vies-<version>.tar.gz) there.

Usage

import "@deckyard/vies/" as vies;

def r as vies.Result init vies.check(vies.client(), "IE", "IE 6388047V");
io.printf("%s %s\n", $r.valid, $r.name);

vies.status(c) reports which member states VIES can reach now. examples/check.j checks the numbers given as arguments, or asks the Commission's test service (vies.sandboxClient()) without them.

Requirements

Jennifer 0.26.0 or newer, with the net capability: the checks are SOAP requests to the Commission's VIES service, over the bundled soap module, and status a GET over the bundled http module.

Development

tools/check-all.sh                 # the full gate, as CI runs it
jennifer test src/vies_test.j      # the test overlay
tools/check-docs.sh                # docs against the code
tools/pack.sh dist                 # build the release archive

Licence

LGPL-3.0-only, see LICENSE. Copyright (C) 2026 mplx <mplx@jennifer-lang.dev>.

tools/check-headers.sh checks every source file's SPDX header against deck.toml.