MDB B2B Check
Checks EU VAT IDs, Swiss UIDs, EORI numbers, Peppol e-invoicing, LEI and IBANs live in the official registers, with source and time. Free, no account, no sign-in. Published by MDB Group s.r.o., Bratislava.
Connect
Server address (MCP, Streamable HTTP, no authentication):
https://b2b.mdb-group.info/mcpClaude (claude.ai and desktop app)
- Open Customize → Connectors.
- Select + and then Add custom connector.
- Name:
MDB B2B Check. URL: the address above. No sign-in is needed. - In a chat, ask for example: “Is SK2120577756 a valid VAT ID?”
Custom connectors need a paid Claude plan. Once the app is listed in the Claude directory, you can add it from there instead.
ChatGPT and other assistants
Any assistant that supports remote MCP servers can use the address above without sign-in. In ChatGPT, use the app from the app directory once it is listed there.
Web page
Without an assistant: b2b.mdb-group.info checks up to 10 numbers at once and offers a full partner check.
Tools
All tools only read data. None of them changes anything, sends anything on your behalf or costs money.
| Tool | What it does |
|---|---|
check_vat_id | Checks one EU VAT ID in VIES or one Swiss UID in the UID register: valid or not, registered name and address where published, source and time. Optional: your own EU VAT ID for an official consultation number, and an expected name and address to compare. |
check_vat_ids | Checks up to 20 numbers at once. |
validate_vat_format | Checks format and check digit of up to 100 numbers without querying a register. |
vies_status | Shows which national VIES services are available right now. |
find_swiss_company | Finds a Swiss company's UID by name, optionally with town. |
check_eori | Checks up to 10 EORI customs numbers in the EU EORI service. |
find_peppol_participant | Finds whether a company can receive e-invoices via Peppol, by VAT ID or name. |
find_lei | Finds a Legal Entity Identifier with direct and ultimate parent, by code or name (GLEIF). |
check_business_partner | One step for a partner: VAT ID, EORI, Peppol and LEI, with a short summary. |
check_iban | Checks an IBAN's format and check digits and compares its country with the partner's. Does not verify who owns the account. |
get_exchange_rate | ECB reference rate for a date (or the last business day before it), with conversion of an amount. |
Ready-made prompts: “Check a supplier before invoicing”, “Check a list of VAT IDs”, “Explain a result”, “Full check of a business partner”.
Example questions
- “Is SK2120577756 a valid VAT ID? Who is it registered to?”
- “Check these suppliers: ATU33864707, FR40303265045, CHE-105.829.940 MWST.”
- “Check ESA28015865. My own VAT ID is SK2120577756, I need a consultation number for my files.”
- “Do a full partner check for BE0886776275. Can they receive e-invoices?”
- “The invoice from ATU33864707 shows IBAN SK31 1200 0000 1987 4263 7541. Anything unusual?”
- “ECB rate for CHF on 6 November 2026, convert 1,000 CHF.”
Results
| Status | Meaning |
|---|---|
| valid | The official register confirms the number. |
| invalid | The official register says the number is not valid. |
| unavailable | The register did not answer or is overloaded. The number could not be checked; this says nothing about whether it is valid. Try again later. |
| format_error | The number cannot exist (wrong length, characters or check digit). No register was queried. |
| unsupported | Country not covered, for example the United Kingdom (except Northern Ireland, XI). |
Every result includes a ready-to-file record with source and time. Results are information only, not tax or legal advice. Some countries do not publish name or address in VIES.
Limits
- Up to 20 numbers per batch check, 100 per format check, 10 EORI numbers per call.
- The official sources have their own limits and outages; the app does not retry automatically and waits at most 10 seconds per source.
- The web page allows about 30 checks per visitor every 10 minutes.
- The Swiss UID register service used here is planned to end in 2028.
Data
- No account, no cookies, no advertising, no training of AI models.
- Your input goes only to the official source that answers the question. IBANs are checked within the app.
- Simple check results are kept for up to 24 hours to avoid repeated lookups. Checks with your own VAT ID or a name to compare are not kept.
- Logs contain no VAT numbers, names, addresses or IBANs and are kept for at most 30 days.
- Hosting: Cloudflare Workers. Full details: privacy policy · terms.
Support
apps@mdb-group.info · MDB Group s.r.o., Námestie SNP 478/19, 811 01 Bratislava, Slovakia
Deutsch – Kurzfassung
MDB B2B Check prüft EU-USt-IdNr., Schweizer UID, EORI-Nummern, Peppol-Erreichbarkeit, LEI und IBAN live in den amtlichen Registern. Kostenlos, ohne Konto und ohne Anmeldung.
- Claude: Customize → Connectors → + → Add custom connector. Name
MDB B2B Check, Adressehttps://b2b.mdb-group.info/mcp, ohne Anmeldung. - Andere Assistenten: dieselbe Adresse als MCP-Server eintragen.
- Ohne Assistent: die Webseite nutzen.
Antwortet eine amtliche Quelle nicht, lautet das Ergebnis «nicht prüfbar» und nie «ungültig». Einfache Prüfergebnisse werden bis 24 Stunden zwischengespeichert. In den Protokollen stehen keine Nummern, Namen oder IBANs. Die Ergebnisse sind Informationen und keine Steuer- oder Rechtsberatung. Details: Datenschutz.