temsor API
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LEI Validation

Validates a 20-character Legal Entity Identifier (ISO 17442) with the ISO 7064 mod-97 check digits.

POST /v1/id/lei · 1 credit · deterministic

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POST/v1/id/lei 
{
  "lei": "5493001KJTIIGC8Y1R12"
}
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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.

Every number carries its provenance

Each archived point stores the source URL and a content hash of the page it came from, and the archive is committed to a Merkle root anchored in Bitcoin. Every commitment — with its cutoff, leaf count and anchors — is published at /proof, so you can check for yourself how current the latest one is. The bulletins themselves are public and anyone can read them; what this adds is that a number you quote can be shown to be the number we held on that date, and that it has not been edited since.

You only pay for work

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

Endpointsexpand any row to see the parameters and call it live

Validation1

/v1/id/lei LEI Validation deterministic 1 credit

Validates a 20-character Legal Entity Identifier (ISO 17442) with the ISO 7064 mod-97 check digits.

KYC and MiFID reporting reject an LEI that fails the check digits before anyone looks the entity up. The algorithm is the same family as IBAN (ISO 7064 mod 97-10) over all 20 characters; the remainder must be 1. The first 4 characters are the issuing LOU prefix, the next 14 the entity, the last 2 the check digits. This does not call GLEIF. A checksum-valid LEI can be lapsed, merged, or never issued. Use GLEIF's free API if you need "this legal entity is currently registered".

Parameters

lei* string Legal Entity Identifier, 20 characters.
POST/v1/id/lei 
{
  "lei": "5493001KJTIIGC8Y1R12"
}
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 25 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/id/lei \
  -H "content-type: application/json" \
  -H "x-api-key: fk_live_…" \
  -d '{"lei":"5493001KJTIIGC8Y1R12"}'

JavaScript

const res = await fetch("https://api.temsor.com/v1/id/lei", {
  method: "POST",
  headers: { "content-type": "application/json", "x-api-key": KEY },
  body: JSON.stringify({"lei":"5493001KJTIIGC8Y1R12"})
});
const { data } = await res.json();

Python

import httpx
r = httpx.post("https://api.temsor.com/v1/id/lei",
    headers={"x-api-key": KEY},
    json={"lei":"5493001KJTIIGC8Y1R12"})
data = r.json()["data"]