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Austrian Firmenbuchnummer (FN) Validator
x402
Austrian Firmenbuchnummer (FN) Validator is a paid API for AI agents from toll402.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).
Validates and verifies an Austrian Firmenbuchnummer (company register number) by computing and comparing its modulo-11 check letter offline.
Price / call$0.001
Success—
StatusUnknown
How this service works
Offline validator for an Austrian Firmenbuchnummer (FN), the company register number. Normalizes the numeric part (1-6 digits, left-padded to 6 for calculation), computes the modulo-11 check letter using weights 2,1,2,1,2,1 (Luhn-style digit reduction for products >=9 by subtracting 9) and the standard letter table (0=p,1=a,2=b,3=c,4=d,5=e,6=f,7=g,8=h,9=i,10=k), and compares it to the supplied check letter.
Output
A validation response indicating whether the supplied Austrian Firmenbuchnummer has a correct modulo-11 check letter, based on offline computation without any external registry lookup.
Example use cases
KYB onboarding company number check
“We're onboarding an Austrian supplier and they gave us their company register number FN 98765a — can you verify that this Firmenbuchnummer is actually valid before we proceed?”
Data quality audit of company registry
“I have a spreadsheet of Austrian company numbers and I want to flag any with invalid check letters — start by validating this one: FN 45678b.”
Form input validation before submission
“A user just typed 'FN 12345x' into our registration form — is that a valid Austrian Firmenbuchnummer, or should we show them an error?”
Technical details
Endpoint
POSThttps://toll402.dev/v1/t/fn_at_validateWhen to prefer
Use this endpoint when you need a fast, cheap, offline structural check of an Austrian Firmenbuchnummer — ideal for form validation, KYB pipelines, or data quality audits where you don't need a live registry lookup, just a check-digit verification.
Side effects
- Invalid or missing 'value' field returns an error response
- FN number with non-numeric body or unsupported format may fail to parse
- Check letter not in the expected letter table (p,a,b,c,d,e,f,g,h,i,k) causes validation failure
- Network or payment (x402) issues may prevent the call from completing
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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