Paid services matching “check digit”

GTIN barcode validator: validate and convert GS1 identifiers: GTIN-8, GTIN-12 (UPC-A), GTIN-13 (EAN-13), GTIN-14, GLN and SSCC. Returns the check-digit verdict, the computed correct check digit, the GTIN-14 form with its indicator digit, and conversion between GTIN-8, -12, -13 and -14. No company-prefix split is returned: GS1's prefix-length table is no longer public data. Also computes a missing

UK VAT number format + check-digit test: Checks a UK VAT number's format and HMRC check digits (mod 97 / 9755). Catches fake or mistyped VAT numbers instantly without an HMRC call. Use /v1/business/check to confirm live registration.

Look up a product barcode number: identify and validate EAN-13, EAN-8, UPC-A, UPC-E, GTIN-14, ISBN-13/10, ISSN and ISMN codes (wrong check digits are reported with the correct digit), convert between forms (GTIN-14, EAN-13, UPC-A, ISBN-10 <-> 13) and decode the GS1 prefix. Then fetch product data from open databases: name, brand, quantity, categories, image, labels, Nutri-Score (food, cosmetics, p

Validates an 18-digit Mexican CLABE (sent as a JSON body, not a query param): check digit, bank identification (Banxico/SPEI catalog), plaza, and account number.

Use when you need to check whether an IBAN is valid and extract its country, bank code and check digits.

Validate a number by the Luhn (mod-10) algorithm — the scheme behind credit/debit card numbers and many IDs. Spaces and hyphens are ignored. A mismatched check digit is a successful { valid: false }.

Validate an NZ bank account number check digit (IRD algorithms A-G/X), normalise BB-bbbb-AAAAAAA-SSS and identify the bank code

Strait of Hormuz shadow-fleet risk screen: the live-AIS vessel population (seen in the last 1.5h) ranked worst-first, each hull with its risk band, typed reasons (ofac_sdn, ais_dark, foc_tanker, imo_spoofed (tanker or cargo IMO fails check digit)), the sanctions bodies listing it (US OFAC, UK/FCDO) and a lastSeenAt timestamp. A transparent rules engine, not ML. Lists flagged hulls (high + moderate

Validates the ISO 6346 check digit and separates owner, category and serial components. Missing facts are returned as null and named in unavailable_fields where applicable. Derived values disclose their method; source-backed values disclose source, time window and age.

Resolve a 20-character Legal Entity Identifier (LEI, ISO 17442) to its authoritative entity record: verified legal name, registration status (ISSUED/LAPSED/RETIRED), entity status, jurisdiction, legal form, registration number, legal and headquarters addresses, key dates (registration, last update, next renewal), managing LOU, corroboration level and any BIC codes. ISO 7064 check digits are verifi

Decode a 17-character VIN: ISO 3779 structural validation (check digit), WMI manufacturer lookup, model year, and NHTSA vPIC pattern decode (make, model, trim, body, engine, plant). Public-domain NHTSA data.

Use when an agent has the text of a Japanese invoice or receipt (e.g. OCR output) and needs exact amounts without LLM misreads. Returns registration number (T+13, check digit only, not an NTA registry lookup), total, subtotal, 8%/10% tax breakdown and issue/due dates (Reiwa to ISO). Deterministic rules; text only, no images/PDF. Errors before payment (no charge): 400 body not {text} or over 5000 c

South African SA ID number validation: Structural validation of a South African identity number with safe decode: Luhn check digit, birth date, gender and citizenship segments (citizen or permanent resident). The structural step in KYC, KYB and customer onboarding or due diligence workflows: derive date of birth, age, gender and citizenship without storing the identity. Run it before a paid regist

ISBN-10/13 check-digit validate + Open Library metadata (polite User-Agent).

Exact-match OFAC wallet screening and crypto wallet sanctions check for sanctioned digital currency addresses. Screens one wallet address against Treasury's public SDN advanced XML and returns hit or clear status, asset coverage, sanctioned entity metadata, sanctions programs, list source, listing date, and a manual-review signal for onchain payment and treasury controls.

Offline structural validator for an Indian CIN (Corporate Identity Number, 21 characters). Parses and checks: listing status letter (L/U), 5-digit NIC industry code, 2-letter state code (against the known MCA state-code list), 4-digit incorporation year (plausible range), 3-letter company-type/ownership code (against a known enum like PLC, PTC, OPC, GOI, NPL, FTC, SGC, ULL, ULT), and 6-digit regis

Counterparty pre-check for a Brazilian company: GET /preflight-cdp?q=<CNPJ (14 digits) | LEI code | company name>, e.g. ?q=68964713000109. Returns entity, status, band (clear/flagged/insufficient_data), flags and sources (Receita Federal, TCU, CNIA, CEIS, CNEP, CVM / GLEIF). Missing or invalid q = 400, no payment settled. — Mesmo dado do /preflight, liquidado pelo Facilitador CDP da Coinbase.

Crypto wallet sanctions check (OFAC): is this blockchain address on the US Treasury OFAC sanctions lists? Exact match against all 1,000+ digital currency addresses OFAC publishes on SDN and Consolidated entries (Bitcoin, Tron, Ethereum and EVM chains, USDT, Litecoin, Monero and more), returning the listing's program and entry ID. Use before sending or accepting a crypto payment. No tracing or risk

Monitor recent official Israeli company-registry changes for an exact nine-digit company number. Returns filing and status-change events newest first, with dates, deterministic categories, source URLs, and checked_at. Use for counterparty monitoring, supplier due diligence, onboarding refreshes, corporate-event alerts, and registry change detection. Coverage is approximately one year.

What a digital-product seller actually keeps per sale on Stripe Payment Links, Lemon Squeezy, Payhip, Ko-fi, Etsy and Gumroad (direct and Discover) at any price you pass: fees, keep, fee %, a ranking, merchant-of-record (who owes sales tax/VAT), extras such as international, PayPal and ads surcharges, subscription break-evens, vendor source URLs and per-row check dates. Rows older than 45 days are

Stop opening five explorers to price one transaction: one GET returns what each chain is charging for gas right now — for base, eth, arbitrum, optimism and polygon: the current gas price in gwei (with the raw wei the RPC returned), the latest block's base fee, the priority fee a 50th-percentile transaction actually paid across the last five blocks, the next block's base fee under the EIP-1559 form