Eurekall

A free, public MCP server that gives AI agents reliable EU business lookups: VAT numbers, exchange rates, public holidays and working days. No sign-up, no API key.

MCP endpoint (Streamable HTTP): https://eurekall.borisano.com/mcp

Tools

All tools are read-only. Answers come as structured JSON plus the same JSON as text.

Tool	What it does
`validate_vat`	Checks one EU VAT number against the European Commission's VIES service. Answers `valid`, `invalid` or `unavailable` (VIES or the member state did not answer; never a verdict). With your own VAT number as `requester_vat` it returns the VIES consultation number.
`validate_vat_batch`	Up to 20 VAT numbers in one call, same meaning per item.
`is_holiday`	Is a date a public holiday, a weekend day or a working day in a country (optionally a region such as `PT-30`)?
`working_days_between`	Counts working days between two dates in a country or region.
`add_working_days`	The date N working days after (or before) a date, e.g. an invoice due date.
`fx_rate`	The ECB euro reference rate of a currency on a date.
`convert`	Converts an amount between two currencies with ECB reference rates, exactly and rounded to the currency's minor units.

Weekends and dates without an ECB fixing fall back to the most recent earlier fixing; the answer states both the requested date and the rate date. Working days are Monday to Friday minus public holidays.

Use in Claude as a custom connector

Eurekall is not listed in the Claude Connectors Directory; add it yourself as a custom connector. It needs no authentication.

In Claude (web or desktop), open Settings → Connectors and choose Add custom connector. On Team and Enterprise plans an owner adds it first under the organization's connector settings.
Name: Eurekall
Remote MCP server URL: https://eurekall.borisano.com/mcp
Leave the OAuth fields empty and select Add.
In a conversation, enable Eurekall in the tools menu, then ask, for example: “Is IE6388047V a valid VAT number?”, “Convert 250 USD to JPY at the ECB rate of 26 September 2026”, or “When is an invoice dated 28 December 2026 due with 30 working days in Portugal?”

See Anthropic's help article on custom connectors using remote MCP for the current screens.

Other MCP clients

Any client that speaks Streamable HTTP can connect. Claude Code:

claude mcp add --transport http eurekall https://eurekall.borisano.com/mcp

A client that takes a JSON configuration (for example Cursor's mcp.json):

{
  "mcpServers": {
    "eurekall": { "url": "https://eurekall.borisano.com/mcp" }
  }
}

Limits and fair use

Per client (IP address): 30 units per minute and 1,000 per UTC day. Every call costs 1 unit; validate_vat_batch costs 1 unit per distinct well-formed number. Over the limit, tools answer rate_limited with retry_after_seconds.
VAT answers are cached (valid for 24 hours, invalid for 6 hours) unless you pass requester_vat, which always asks VIES live.
This is a free personal project with no uptime guarantee.

Data sources

VAT: VIES, European Commission. A VIES answer confirms registration for intra-EU trade; it is not legal or tax advice.
Exchange rates: ECB euro foreign exchange reference rates (published around 16:00 CET on TARGET business days).
Public holidays: Nager.Date.

Eurekall is not affiliated with the European Commission, the ECB or Nager.Date.