Description
Business customers enter their Swiss business identification number (UID, in German “Unternehmens-Identifikationsnummer”) in the checkout or in a quote form. Strainovic UID Check Schweiz validates it before the order or request goes through:
- Format and check digit instantly, without a network request (CHE-123.456.789, also without separators or with the suffix MWST/TVA/IVA)
- Existence in the UID register of the Swiss Federal Statistical Office
- Status: deleted or unknown companies are rejected with a clear message in the form
- Consistent format in the order (CHE-123.456.789)
- If the UID register is unreachable, the order is not blocked as long as the check digit is correct
- Results are cached for one day, so each UID is requested at most once per day
WooCommerce: the plugin adds an optional “UID” field to the checkout, both to the Checkout block (default since WooCommerce 8.3, contact section, saved to the customer account) and to the classic shortcode checkout (after the company name). If filled in, it is validated.
Contact Form 7: every text field named uid is validated, for example [text uid placeholder "CHE-123.456.789"], or [text* uid] for a required field.
Languages: English, German (Germany and Switzerland), French and Italian are included. The field label and the error messages follow the language of the site, with the Swiss terms UID, IDE (French) and IDI (Italian). German variants such as de_CH_informal or de_AT, and French or Italian variants such as fr_CA or it_CH, use the matching bundled translation.
Pro version (in preparation): fill in company name, legal form and address automatically from the register, show the VAT status, allow invoice payment only for valid companies, alert when a customer company is deleted. More at https://www.strainovic-it.ch/uid-check/
External services
This plugin connects to the public UID web service of the Swiss Federal Statistical Office (FSO, in German “Bundesamt für Statistik”, BFS). The service gives access to the official Swiss UID register (https://www.uid.admin.ch/).
What it is used for: to check whether a Swiss business identification number (UID) entered by a customer exists in the UID register and whether the company is still active. Unknown and deleted UIDs are rejected with an error message.
When data is sent: only when a filled-in UID field is validated: when a checkout or a Contact Form 7 form is submitted, when the WooCommerce Checkout block saves the entered UID while the customer fills in the checkout, or when a customer saves the UID in the account details. In every case only after the UID has passed the local format and check digit validation. Invalid input never leaves the website. The answer is cached for one day, so the same UID is sent at most once per day. Nothing is sent when the UID field is empty, and nothing is sent in the background.
What data is sent: only the nine digits of the entered UID (for example 353272857 for CHE-353.272.857), in a SOAP request to the “GetByUID” operation. No name, address, email or other customer data is sent. The request is made by the website’s server, not by the visitor’s browser, so the visitor’s IP address is not transmitted; like every WordPress HTTP request, it carries the server’s IP address and WordPress’s default user agent (WordPress version and site address).
- Service provider: Swiss Federal Statistical Office (FSO), Espace de l’Europe 10, 2010 Neuchâtel, Switzerland
- Endpoint: https://www.uid-wse.admin.ch/V5.0/PublicServices.svc
- Service description: https://www.bfs.admin.ch/bfs/en/home/registers/enterprise-register/enterprise-identification/uid-register/uid-interfaces.html
- Terms of use: https://www.admin.ch/en/terms-and-conditions
- Privacy policy: https://www.admin.ch/en/terms-and-conditions#Privacy-Notice
- UID register legal basis and data protection: https://www.bfs.admin.ch/bfs/en/home/registers/enterprise-register/enterprise-identification/uid-general/legal-basis-data-protection.html
Screenshots

Installation
- Search for “Strainovic UID Check Schweiz” under Plugins Add New, or upload the folder
strainovic-uid-check-schweizto/wp-content/plugins/. - Activate the plugin.
- WooCommerce: the field appears in the checkout automatically. Contact Form 7: add a text field named
uidto your form.
FAQ
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Is the field required?
-
In the WooCommerce checkout it is optional and only validated when filled in. In Contact Form 7 you decide with
[text uid]or[text* uid]. -
What happens if the UID register is down?
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A UID with a correct check digit is accepted. An outage of the federal service should never block an order.
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Do I need an account or API key?
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No. Public queries of the UID register are free and need no login.
Reviews
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Contributors & Developers
“Strainovic UID Check Schweiz” is open source software. The following people have contributed to this plugin.
ContributorsTranslate “Strainovic UID Check Schweiz” into your language.
Interested in development?
Browse the code, check out the SVN repository, or subscribe to the development log by RSS.
Changelog
0.2.1
- Renamed to “Strainovic UID Check Schweiz” with the slug and text domain strainovic-uid-check-schweiz; the Checkout block field is now strainovic-uid-check-schweiz/uid.
- The “External services” section describes in detail which data is sent to the UID register and when.
0.2.0
- Translations: English source texts, bundled German (de_DE, de_CH), French and Italian translations for the checkout field and all error messages.
0.1.1
- Checkout block support via the additional checkout fields API; the UID is validated on the Store API and saved to the order in a consistent format.
0.1.0
- First release: UID validation in WooCommerce checkout and Contact Form 7.
