{"uid":"cap_Lc9bvPjyii7CdtSCDO5az","slug":"verify-uk-vat-number-format-check-digit-validator-09ca36f5","name":"Verify UK VAT Number Format & Check-Digit Validator","description":"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.","url":"https://verify-uk.verifyuk.workers.dev/v1/validate/vat?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["vat"],"properties":{"vat":{"type":"string","description":"UK VAT number, with or without GB"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"notes":["Right length, but fails the HMRC check-digit test."],"valid":false}},"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_BrbVceTu4fp3bQcSwR2lJ","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 a UK VAT number's format and HMRC check-digit (mod 97/9755) without making a live HMRC registration call","exampleAgentPrompt":"Can you check whether the VAT number GB123456789 is correctly formatted and passes the HMRC check-digit test — without doing a live HMRC lookup?","exampleUseCases":[{"title":"Screen supplier VAT numbers at onboarding","prompt":"I'm onboarding a new UK supplier and they gave me VAT number GB294627287 — can you quickly check if it's a valid format and passes the check-digit test before I add them to our system?"},{"title":"Catch typos in user-submitted VAT fields","prompt":"A customer just entered 123456780 as their UK VAT number on our checkout form — can you validate the format and check-digits to see if it's likely a typo or fake?"},{"title":"Pre-screen VAT numbers before HMRC API call","prompt":"Before I use an HMRC lookup to confirm live registration, can you first validate whether GB999999973 even has the right format and passes the mod 97 check-digit test?"}],"resultDescription":"A JSON object containing a 'valid' boolean indicating whether the VAT number passes format and check-digit validation, plus a 'notes' array with human-readable explanations of any failures (e.g. wrong length, failed HMRC check-digit test).","failureModes":["Missing 'vat' query parameter — returns error indicating required field is absent","VAT number with invalid characters — flagged as invalid format with explanatory note","Network timeout on the Cloudflare Worker — transient failure, retry recommended","VAT number that looks correct in length but fails mod 97/9755 check — returns valid:false with a note explaining the check-digit failure"],"whenToPreferThis":"Use this endpoint when you need fast, free-of-HMRC-quota format and check-digit validation of a UK VAT number — ideal for pre-screening user inputs, catching typos, or filtering obviously fake numbers before spending an HMRC live-lookup call. Prefer this over /v1/business/check when you don't need to confirm active registration, just structural validity.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-30T12:32:10.792Z","isFirstParty":false,"canonicalSlug":"verify-uk-vat-number-format-check-digit-validator-09ca36f5"}