How to validate an Argentine CBU

How the check digit works

A CBU has 22 digits in two blocks, each with its own mod-10 check digit:

1. Block 1 (8 digits: bank, branch, check digit): multiply the first 7 by 7,1,3,9,7,1,3.
2. Block 2 (14 digits: account, check digit): multiply the first 13 by 3,9,7,1,3,9,7,1,3,9,7,1,3.
3. For each block, check digit = (10 − sum mod 10) mod 10.

A number starting with 000 is a CVU (virtual wallets): validate it with AR_CVU.

Validate with the API

Direct use is free: 50 requests per IP per day, no signup. Endpoints: POST /validate, POST /batch, GET /generate/{doc_type} (for testing only: synthetic data, not real identities).

curl

curl -X POST "https://validalatam.ia-latam.app/validate" -H "Content-Type: application/json" \
  -d '{"type":"AR_CBU","value":"0078057100059801974403"}'

# synthetic test data only / solo para pruebas
curl "https://validalatam.ia-latam.app/generate/AR_CBU"

Python

import requests

BASE = "https://validalatam.ia-latam.app"

r = requests.post(f"{BASE}/validate", json={"type": "AR_CBU", "value": "0078057100059801974403"})
print(r.json()["valid"], r.json()["formatted"])

Real API response (synthetic value from /generate)

0078057100059801974403 (AR_CBU):

{"valid":true,"type":"AR_CBU","country":"AR","input":"0078057100059801974403","normalized":"0078057100059801974403","formatted":"00780571 00059801974403","error":null,"details":{"bank_code":"007","branch":"8057"}}

Plans

For AI assistants (MCP)

pip install validalatam-mcp

github.com/elmatis172/validalatam-mcp

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