W System / Terms of service, version 1 (archived)

Terms of service, version 1 (archived)

This version is no longer in force. It applied until 21 October 2026 and was replaced by version 2.

These terms apply to the W System API at api.wsystem.dev, the MCP server and the free tools on wsystem.dev (together, the "Service"), including when the Service is called by our integrations such as the W System VIES Check plugin for WordPress. The plugin software itself is licensed under the GPLv2 or later; these terms cover only the online Service.

Provider: W System Hungary Kft., EU VAT: HU33119856. Contact: [email protected]; see also the imprint.

1. The Service

The Service checks EU VAT numbers against the European Commission VIES service, provides other lookups from public official sources, and offers e-invoicing tools (validation, creation, routing, sandbox sending and, under separate terms, live Peppol sending). Results reflect what those sources return at the time of the request. We are not affiliated with the European Commission or any tax authority, including HMRC.

1a. UK VAT number checks

GB VAT numbers are checked with HM Revenue & Customs' "Check a UK VAT number" API. Until our production access is active, GB results are a local format and check-digit validation (or clearly marked sandbox test data) and are flagged as such. Results reflect what HMRC returns at the time of the request. W System is independent and is not affiliated with, endorsed or approved by HMRC. You must not use the Service to check UK VAT numbers for unlawful purposes or in bulk beyond what you need for your own business checks. We never ask for your HMRC credentials.

2. Free tier and paid access

• Free tier: 20 calls per day per client IP address, no account or key needed.
• Higher volume: x402 pay-per-call, Apify Actors, or a monthly plan with an API key (Starter or Pro; Peppol plans with live Peppol documents once live sending opens). Prices are shown on the pricing page and exclude VAT.
• Monthly plans are sold through Stripe Managed Payments: Stripe acts as reseller and merchant of record, takes the payment, calculates and collects any VAT or sales tax, and its checkout terms apply to the purchase. W System provides the Service under these terms. You can cancel a plan at any time.
• When a quota is used up the API answers with HTTP 429 or 402 until the next day or until payment.

3. Acceptable use

Do not use the Service unlawfully, try to get around quotas (for example by rotating IP addresses), resell raw access without permission, or send loads that harm the Service or the official sources behind it. We may limit or block abusive use.

3a. Your content

You are responsible for the data and documents you submit, for example invoice contents, VAT numbers and company details, and for having the right to submit them. We process them as you instruct; we do not check or approve their commercial or tax content. If you use the Service as a business, you indemnify W System, and for live Peppol sending also our access point partner E-invoice BV, against third-party claims, fines imposed by authorities and reasonable costs (including reasonable legal fees) to the extent they result from content you submit or from your breach of section 3. We will tell you promptly about such a claim, let you take part in the defence and not settle it at your expense without your consent, which you will not unreasonably withhold.

4. No advice, no warranty

Results are not legal or tax advice. You remain responsible for your VAT treatment. The Service is provided "as is"; official sources can be unavailable or wrong, and we do not guarantee uninterrupted availability.

5. Liability

To the extent permitted by law, we are not liable for indirect or consequential loss, lost profits or lost data, and our total liability under these terms and the Peppol mandate terms together is limited to the greater of (a) the amounts you paid us for the Service in the 12 months before the event giving rise to the claim and (b) €100. This does not limit or exclude liability for damage caused intentionally or by gross negligence, for harm to life, physical integrity or health, or any other liability that cannot be limited under applicable law.

6. Personal data

See the privacy policy. Where we process e-invoices and other business documents on your behalf, our Data Processing Agreement applies.

6a. Live Peppol sending

Before a company can send or receive e-invoices over the Peppol network through W System, a person authorised to bind it accepts the Peppol mandate and live sending terms (through the API). Those terms apply in addition to these terms and take precedence for live sending.

7. Changes and law

We may update these terms; the date below shows the current version. These terms are governed by Hungarian law. The courts of Budapest, Hungary have exclusive jurisdiction for disputes with business customers. If you are a consumer, the mandatory consumer protection rules and the courts of your country of residence remain available to you.

Last updated 2026-10-21.