{"uid":"cap_WdereROow4m7j4cbaYw9B","slug":"qr-code-capacity-lookup-iso-18004-7468cdb0","name":"QR Code Capacity Lookup (ISO 18004)","description":"QR capacity from the ISO 18004 table: max digits, letters, bytes for a version, or the smallest version for a length.","url":"https://barcode-qr.x402tookit.com/qr-capacity?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":["ec"],"properties":{"ec":{"type":"string","description":"Error correction level L, M, Q or H"},"mode":{"type":"string","description":"numeric, alphanumeric or byte (default byte) for the length search"},"length":{"type":"integer","description":"Characters to store: returns the smallest version that fits"},"version":{"type":"integer","description":"QR version 1 to 40: returns every mode's capacity"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"asOf":{"type":["null","string"]},"source":{"type":["null","string"]},"ecLevel":{"type":["null","string"]},"reasons":{"type":["array","null"],"items":{"type":"string"}},"summary":{"type":["null","string"]},"verdict":{"type":["null","string"]},"version":{"type":["null","object"],"properties":{"modules":{"type":["null","number"]},"version":{"type":["null","number"]},"maxBytes":{"type":["null","number"]},"maxKanji":{"type":["null","number"]},"maxDigits":{"type":["null","number"]},"dataCodewords":{"type":["null","number"]},"totalCodewords":{"type":["null","number"]},"maxAlphanumeric":{"type":["null","number"]},"errorCorrectionBlocks":{"type":["null","number"]},"errorCorrectionCodewords":{"type":["null","number"]},"errorCorrectionCodewordsPerBlock":{"type":["null","number"]}}},"degraded":{"type":["boolean","null"]},"disclaimer":{"type":["null","string"]},"notChecked":{"type":["array","null"],"items":{"type":"string"}}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","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":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_QON2Q-J0Sgt1PfoAQPJQp","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns QR code capacity limits from the ISO 18004 table — max digits, alphanumeric, and bytes for a given version, or finds the smallest version that fits a given data length.","exampleAgentPrompt":"What is the maximum number of bytes and alphanumeric characters a version 10 QR code can store at error correction level M? Also, what is the smallest version I would need for a 250-character alphanumeric string at error correction Q?","exampleUseCases":[{"title":"Pre-generation capacity validation","prompt":"Before I generate a QR code, check if QR version 5 with H error correction is large enough to hold 120 alphanumeric characters — tell me the exact capacities for all modes."},{"title":"Smallest version finder for URL encoding","prompt":"I have a URL that is 180 bytes long. What is the smallest QR version that can fit it using byte mode with M error correction?"},{"title":"Capacity planning for numeric data","prompt":"I'm encoding a 16-digit serial number in numeric mode. What QR version do I need at error correction level L, and how many digits could the same version handle at level H?"}],"resultDescription":"Returns a structured object containing the matched QR version's full capacity profile: max digits, max alphanumeric characters, max bytes, max kanji, data codewords, total codewords, error correction codewords and blocks per block, module grid size, and the error correction level used. When searching by length, it returns the smallest version that satisfies the request.","failureModes":["Missing required 'ec' parameter returns an error","Invalid error correction level (not L, M, Q, or H) returns a validation error","Version out of range (not 1–40) returns an error","Length too large to fit in any QR version returns no matching version","Invalid mode string returns a validation error","Conflicting parameters (both version and length omitted) may return ambiguous results"],"whenToPreferThis":"Choose this endpoint when you need to programmatically determine QR code capacity before generating a code, validate whether data will fit in a target version, or find the optimal version for a given payload length. It is a pure ISO 18004 table lookup — ideal for pre-flight checks before calling a QR SVG generator, capacity planning for barcode workflows, or building dynamic QR systems that select version based on content length. It is faster and cheaper than generating a full QR SVG just to check capacity.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-11-02T18:32:39.283Z","isFirstParty":false,"canonicalSlug":"qr-code-capacity-lookup-iso-18004-7468cdb0"}