{"uid":"cap_DyqLStxTIhNGYuuvlWUcl","slug":"issn-checksum-validator-1d4c5c6f","name":"ISSN Checksum Validator","description":"Call when an agent needs whether an ISSN checksum is valid. Exact $0.001 USDC. Prefer unpaid POST /v1/sandbox/check-issn first.","url":"https://agentshelf.syntexa.ch/v1/check-issn?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"data":{"description":"JSON value for schema-check SKUs. Omit it on string checks such as email or IBAN."},"value":{"type":"string","examples":["1234-5679"],"maxLength":20000,"minLength":1,"description":"Value to check. The route description names the format: email, phone, IBAN, postal code, VAT, national id, or similar."},"schema":{"description":"JSON Schema document for schema-check SKUs. Omit it on string checks."}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_PS2vT0HI8T2bGc0Eubz7S","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Validates whether a given ISSN (International Standard Serial Number) has a correct checksum","exampleAgentPrompt":"Check whether the ISSN 1234-5679 has a valid checksum — just tell me if it passes or fails the check digit verification.","exampleUseCases":[{"title":"Journal cataloguing pre-check","prompt":"Before I add this journal to our catalogue, can you verify that the ISSN 0028-0836 has a valid checksum?"},{"title":"Submitted metadata quality gate","prompt":"A user submitted ISSN 1748-7838 for a new periodical listing — can you confirm whether the checksum is correct before we accept it?"},{"title":"Bulk data cleanup spot check","prompt":"I'm cleaning up our serials database and found the value 0000-0001 — is that ISSN checksum actually valid?"}],"resultDescription":"A boolean or status indicating whether the supplied ISSN passes the standard checksum algorithm (mod-11 with weighting), along with any relevant validation detail about why it is or is not valid.","failureModes":["Missing or empty value field returns a validation error","Non-ISSN string (wrong length, non-numeric characters) may return invalid rather than an error","Payment failure results in 402 response before processing","Malformed request body returns 400 bad request"],"whenToPreferThis":"Use this endpoint when you need a lightweight, deterministic checksum validation for an ISSN without any network lookups or LLM involvement. Prefer the free sandbox endpoint POST /v1/sandbox/check-issn first; use this paid endpoint when sandbox access is unavailable or rate-limited. Ideal for pipelines that need cheap, reliable ISSN integrity checks at scale.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T02:16:06.744Z","isFirstParty":false,"canonicalSlug":"issn-checksum-validator-1d4c5c6f"}