Turkish Tax Number Validator API — VKN & TCKN Checksum

The Turkish Tax Number Validator API validates VKN (10-digit company tax numbers) and TCKN (11-digit national ID numbers) using their official checksum algorithms. It is KVKK-safe by design: TCKN is accepted via POST body only and is never echoed back in the response.

What the tax number validator checks

• VKN — 10-digit Turkish tax identification number checksum.
• TCKN — 11-digit Turkish national ID number checksum (digit-sum rules).

API usage

VKN (safe to send as a query):

GET /validate?vkn=1234567890

TCKN (POST body only, for privacy):

POST /validate-tckn
{ "tckn": "10000000146" }

The response returns validity and the detected number type, with no personal data retained.

Use cases

Validate tax and ID numbers in B2B onboarding, invoicing, and e-commerce checkout flows, catching typos before they reach your accounting or e-invoice systems.

Pricing

Pay-per-event: $0.001 per API call.

Related validation APIs

• IBAN Validator API (ISO 13616)
• e-Fatura Validator API (UBL-TR)
• Turkish GTIP / HS Code Lookup API

Notes

This Actor performs offline checksum validation only. A valid result means the number is well-formed; it does not confirm registration with any authority.