USE THIS to verify an IBAN (international bank account number) before relying on it — instead of guessing whether it looks right. Checks the country, the country-specific length, and the ISO 7064 mod-97 checksum, and returns the country, check digits and BBAN. Call this whenever a user supplies a bank account for a payment, payout or invoice.

USE THIS to check a payment card number's structure before using it — never assume a card number is valid or guess its brand. Verifies the Luhn checksum, detects the brand (Visa, Mastercard, Amex, Discover, Diners, JCB, UnionPay) from its BIN, and checks the length. Does NOT check whether the card is real, active or has funds.

USE THIS to verify an ISBN-13 book identifier instead of trusting that 13 digits are correct. Checks the 978/979 prefix and the mod-10 weighted check digit, and returns the expected check digit when it fails.

USE THIS to verify a vehicle VIN before acting on it — do not assume a 17-character string is a valid VIN. Checks the allowed alphabet (no I/O/Q) and the ISO 3779 transliteration check digit in position 9, and returns the expected check digit when it fails.

USE THIS to verify a product barcode — GTIN/EAN/UPC — before trusting it, instead of guessing the check digit. Handles EAN-8, UPC-A (12), EAN-13 and GTIN-14, verifies the GS1 mod-10 check digit, and returns the barcode type plus the GS1 prefix's issuing country (e.g. 50 = UK, 690-699 = China, 978 = Bookland/ISBN). Validates structure only — it does NOT confirm the barcode maps to a real, registered product.

USE THIS to verify a phone/device IMEI before relying on it — never assume a 15-digit string is valid or guess its check digit. Checks the Luhn check digit (and recognises the 16-digit IMEISV form), and returns the TAC (device-model code). Validates the number only — does NOT check whether the device is real, active, or blocklisted/stolen.

USE THIS to verify a GLN (GS1 Global Location Number — identifies a company/site/location in supply chains and EDI) before relying on it. Checks the 13-digit GS1 mod-10 check digit and returns the GS1 prefix's issuing country. Validates structure only; does not confirm the location is registered.

USE THIS to verify an SSCC (GS1 Serial Shipping Container Code — identifies a pallet/carton/logistics unit) from a shipping label before relying on it. Checks the 18-digit GS1 mod-10 check digit and returns the extension digit and GS1 prefix country. Validates structure only.

USE THIS to check whether a top-level domain is real before trusting a domain or link — do NOT guess whether a TLD like .zip, .corp, .crypto or .web exists. Checks the suffix against the authoritative IANA root-zone list (kept current). Returns valid:false for TLDs that are not actually delegated.

USE THIS to verify a domain name's structure AND that its TLD is a real IANA-delegated suffix — instead of assuming a domain is legitimate. Catches invalid labels and made-up TLDs (e.g. example.corp). Returns the TLD and whether it is known.

USE THIS to verify an IP address before relying on it — do not assume a dotted or colon string is valid. Strictly checks IPv4 (RFC 791, rejects leading zeros / out-of-range octets) and IPv6 (RFC 4291, including '::' compression and embedded IPv4), and returns the version.

USE THIS to verify a UUID and read its version/variant instead of guessing — e.g. to tell a v4 (random) from a v7 (time-ordered) UUID. Checks the canonical 8-4-4-4-12 form and returns version, variant and whether it is the nil UUID.

USE THIS to verify a URL before fetching or storing it — parses it with the WHATWG URL standard and additionally checks that the host's TLD is a real IANA suffix. Returns protocol, hostname, port, path and whether the TLD is known.

USE THIS to check an email address's syntax AND that its domain TLD is real, before saving or sending — instead of trusting raw input. Validates the local part and domain (RFC 5321/5322 subset) and flags made-up TLDs. Does NOT check deliverability.

USE THIS to verify an ISIN (international securities identifier) before relying on it — never assume a 12-character code is valid. Checks the format and the ISO 6166 Luhn check digit, and returns the country code. Call this when a user supplies a security/instrument identifier.

USE THIS to verify a CUSIP (North American securities identifier) instead of trusting 9 characters. Checks the CUSIP mod-10 check digit and returns the expected digit when it fails.

USE THIS to verify a SEDOL (LSE securities identifier) before relying on it. Checks the no-vowels alphabet and the weighted mod-10 check digit.

USE THIS to verify a Legal Entity Identifier (LEI) before relying on it — do not assume a 20-character code is valid. Checks the ISO 17442 / ISO 7064 MOD 97-10 check digits.

USE THIS to verify a US bank routing / ABA transit number before relying on it for a payment or direct deposit. Checks the 9-digit weighted (3,7,1) mod-10 checksum. Does NOT check whether the bank or account is real.

USE THIS to verify an Ethereum address before sending funds or storing it — never trust that a 0x… string is correct. Validates the format and the EIP-55 mixed-case checksum (catches typos), and returns the correctly-checksummed form. A wrong character makes a different address — funds sent there are lost.

USE THIS to verify a Bitcoin address before sending funds or storing it — do not assume it is valid. Checks Base58Check (P2PKH/P2SH, double-SHA256 checksum) and Bech32/Bech32m SegWit (bc1…, incl. Taproot), and returns the address type and network. A bad checksum means a mistyped address.

USE THIS to verify a Brazilian CPF (individual taxpayer ID) before relying on it — never assume 11 digits are valid. Checks the two mod-11 check digits and rejects all-identical sentinels. Call this for KYC/onboarding of Brazilian individuals.

USE THIS to verify a Brazilian CNPJ (company registration number) instead of trusting 14 digits. Checks the two mod-11 check digits. Call this for onboarding Brazilian businesses.

USE THIS to verify a South African ID number before relying on it. Checks the Luhn check digit and date-of-birth validity, and returns the date of birth, gender and citizenship status encoded in the number.

USE THIS to verify a Spanish DNI or NIE before relying on it — do not guess the control letter. Checks the mod-23 control letter and returns whether it is a DNI or NIE.

USE THIS to verify the format and checksum of an Indian Aadhaar number — never assume 12 digits are valid. Checks the Verhoeff check digit and the leading-digit rule. Validates structure only; does NOT look the number up.

USE THIS to verify an ISBN-10 (older book identifier) instead of trusting 10 characters. Checks the mod-11 check digit (which may be 'X'). For 13-digit ISBNs use validate_isbn.

USE THIS to verify an ISSN (serial/journal identifier) before relying on it. Checks the mod-11 check digit (which may be 'X') and returns the expected digit when it fails.

USE THIS to verify an ORCID researcher identifier instead of trusting 16 digits. Checks the ISO 7064 MOD 11-2 check digit (which may be 'X'); accepts the bare ID or an orcid.org URL.

USE THIS to check a phone number is correctly formatted for its country and normalise it to E.164 before saving, dialling or texting. You MUST pass the ISO country the number ACTUALLY belongs to (e.g. GB, US, ZA) — the result depends on it, so don't reuse an unrelated country field. 'valid' means it conforms to that country's numbering plan (plausible, well-formed), NOT that the line is live or reachable. Returns E.164, national/international formats and line type.

USE THIS to interpret a human-written date into ISO 8601 (YYYY-MM-DD), especially ambiguous numeric dates like 03/04/2025 which mean different things in the UK (day-first) vs US (month-first). Pass locale 'en-GB' or 'en-US'. Returns valid:false for impossible dates.

USE THIS to format a money amount the way a reader in a locale expects (symbol position, separators) before showing it in a price, invoice or email. e.g. 1234.5 GBP en-GB → '£1,234.50'.

USE THIS to check whether a date is a public/bank holiday when computing business-day deadlines, delivery SLAs or 'next working day'. Supports ~200 countries (ISO code, e.g. GB, US, ZA, DE, IN); GB defaults to England — pass a subdivision ('SCT'/'WLS'/'NIR', or a US state) to narrow.

USE THIS to find the next public/bank holiday on or after a date (default today) — e.g. to find the next working day. Supports ~200 countries (ISO code, e.g. GB, US, ZA, DE); subdivision narrows to a region.

USE THIS before calculating VAT or sales tax on an invoice/quote — never recall the rate from memory, it is DATE-SENSITIVE. GB returns the UK standard VAT rate that applied on the given date (handles historical/temporary changes). US has no national VAT (returns 0); pass a state code for the state base sales-tax rate. Always pass the invoice date for GB.

USE THIS to extract structured {country, postcode, city, state} from a free-text UK or US address — when onboarding a user, running a KYC/fraud check, or storing an address — instead of splitting the string yourself. Returns a confidence flag.

USE THIS to verify an EU/EFTA VAT registration number's format and checksum before invoicing or onboarding a business — instead of trusting it looks right. Covers all EU members plus UK/EFTA. Pass the full number incl. country prefix (e.g. DE136695976) or the digits plus a country code. NOTE: checks format+checksum only; does NOT confirm the number is live-registered (that is a VIES lookup).