temsor API
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EU VAT Number Validation

Validates an EU VAT number against the official VIES register, with per-country format checks and honest handling of upstream outages.

POST /v1/eu/vat/validate · 2 credits

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POST/v1/eu/vat/validate 
{
  "vatNumber": "DE811907980"
}
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Why this exists

Built for hostile input

A Turkish address arrives as "Cd." or "Cad." or "Caddesi", with the flat number glued to the building number. Generic parsers drop half of it silently. This one tells you what it could not place.

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Repeated inputs come from cache and cost zero credits. If a response ever fails its own schema, the call is refunded automatically.

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Validation1

/v1/eu/vat/validate EU VAT Number Validation 2 credits

Validates an EU VAT number against the official VIES register, with per-country format checks and honest handling of upstream outages.

VIES is free but unreliable: member-state services drop out individually and a failed lookup can easily be mistaken for a rejection. Treating an outage as "invalid" means charging VAT to a customer who should have been exempt — an error with a price tag. So this endpoint never returns `invalid` when the service could not answer; it returns `unknown` and names the reason, and reports whether that country's service is currently up. Format is checked locally first, so an obvious typo never becomes an upstream call. Results are cached for 24 hours. Note that most member states do not publish the company name; when they do, it is returned.

Parameters

vatNumber* string VAT number with or without the country prefix, e.g. "DE811907980".
countryCode string Country code, when the number is given without a prefix.
POST/v1/eu/vat/validate 
{
  "vatNumber": "DE811907980"
}
no request sent yet
Press Run to call the live API from your browser.

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Use it from an AI assistantthe same catalogue, exposed as MCP tools

Every endpoint is also published over the Model Context Protocol, so Claude, ChatGPT or your own agent can call it directly — no glue code, no wrapper functions. The assistant sees the same input schemas and the same metering.

Currently 12 tools. New endpoints appear automatically; nothing to update on your side.

claude_desktop_config.json

{
  "mcpServers": {
    "temsor": {
      "url": "https://api.temsor.com/mcp",
      "headers": { "x-api-key": "fk_live_…" }
    }
  }
}

Quickstart

Official client: npm install temsor-api · npmjs.com/package/temsor-api

Node.js

import Client from "temsor-api";

const api = new Client({ apiKey: KEY });
const r = await api.${(() => {
  const first = apis[0];
  return first.slug.split(/[/-]/).map((p, i) => (i === 0 ? p : p[0].toUpperCase() + p.slice(1))).join('');
})()}(${esc(JSON.stringify(apis[0].examples[0]?.input ?? {}))});
console.log(r, r.$meta);

cURL

curl -s https://api.temsor.com/v1/eu/vat/validate \
  -H "content-type: application/json" \
  -H "x-api-key: fk_live_…" \
  -d '{"vatNumber":"DE811907980"}'

JavaScript

const res = await fetch("https://api.temsor.com/v1/eu/vat/validate", {
  method: "POST",
  headers: { "content-type": "application/json", "x-api-key": KEY },
  body: JSON.stringify({"vatNumber":"DE811907980"})
});
const { data } = await res.json();

Python

import httpx
r = httpx.post("https://api.temsor.com/v1/eu/vat/validate",
    headers={"x-api-key": KEY},
    json={"vatNumber":"DE811907980"})
data = r.json()["data"]