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Card / IBAN validator
Card / IBAN validator
Luhn check for credit cards (with issuer detection) and mod-97 check for IBAN.
Credit card
Luhn algorithm + issuer detection
IBAN
Mod-97 check + length per country
Card number
Valid card number
Luhn check passes.
Issuer:
Visa
, Masked:
453201••••••0366
Dev utilities
All tools
Text stats
Characters, words, lines, sentences, reading time and approximate LLM token count.
Diff tool
Compare two blobs of text side-by-side or as a unified diff. Whitespace and case toggles.
HTTP status lookup
Search the full list of HTTP status codes: number, reason phrase, category and meaning.
User-Agent parser
Break down a User-Agent string into browser, engine, OS, device and bot heuristics.
IP / CIDR calculator
IPv4 and IPv6 CIDR math: network, broadcast, first / last host, mask, host count, classification.
Punycode converter
Convert internationalised domain names (IDN) to ASCII Punycode and back.