validate

Deterministic identifier validation for AI agents.

An LLM asked to validate a credit card number will pattern-match the digits and miss the Luhn check. IBANs have mod-97 checksums, UUIDs have variant bits, emails have RFC 5322 rules no model memorises correctly. Euclid's validate tool applies the real algorithms — check digits, structural rules, and format standards — so your agent never approves a malformed identifier.

Live

euclid / validate

validate({ operation: "email", input: "user+tag@example.co.uk" }){ "valid": true, "details": { "local": "user+tag", "domain": "example.co.uk" } }

validate({ operation: "credit_card", input: "4111111111111111" }){ "valid": true, "details": { "network": "Visa", "luhn": true } }

validate({ operation: "iban", input: "DE89370400440532013000" }){ "valid": true, "details": { "country": "DE", "checkDigits": "89" } }

validate({ operation: "uuid", input: "550e8400-e29b-41d4-a716-446655440000" }){ "valid": true, "details": { "version": 4, "variant": "RFC 9562" } }

Operations

email (RFC 5322)url (WHATWG)uuid (RFC 9562)credit card (Luhn)ipv4ipv6iban (mod-97)

Examples

What it looks like in practice

Validating a customer email with subaddressing

validate({ operation: "email", input: "user+tag@example.co.uk" })

{ "valid": true, "details": { "local": "user+tag", "domain": "example.co.uk" } }

Checking a credit card with Luhn verification

validate({ operation: "credit_card", input: "4111111111111111" })

{ "valid": true, "details": { "network": "Visa", "luhn": true } }

Verifying an IBAN before initiating a wire transfer

validate({ operation: "iban", input: "DE89370400440532013000" })

{ "valid": true, "details": { "country": "DE", "checkDigits": "89" } }

Checking a UUID version and variant

validate({ operation: "uuid", input: "550e8400-e29b-41d4-a716-446655440000" })

{ "valid": true, "details": { "version": 4, "variant": "RFC 9562" } }

Validating an IPv6 address from a firewall log

validate({ operation: "ipv6", input: "2001:0db8:85a3::8a2e:0370:7334" })

{ "valid": true, "details": { "normalized": "2001:0db8:85a3::8a2e:0370:7334" } }

Catching an invalid URL before making an API call

validate({ operation: "url", input: "htp://not-a-valid-url" })

{ "valid": false, "error": "Protocol 'htp' is not validated — only http and https" }

Who uses this

Built for agents across every domain

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Payment processor

An agent validating card numbers with the Luhn algorithm before sending to the payment gateway — rejecting typos at the source, not at Stripe.

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Banking compliance officer

Verifying IBAN check digits on incoming wire transfers. A single transposed digit means the payment routes to the wrong account.

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Identity platform engineer

Validating email addresses at sign-up using RFC 5322 rules — catching edge cases like missing TLDs and invalid characters that regex approximations miss.

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Network administrator

An AI agent checking whether IPv4 and IPv6 addresses in firewall rules are structurally valid before applying the configuration.

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API developer

Validating UUIDs from webhook payloads — ensuring version and variant bits are correct before writing to the database.

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Fintech startup

An onboarding agent that validates IBANs, credit cards, and emails in a single flow — every check uses the real algorithm, not a regex guess.

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