{"uid":"cap_3Yyuwyzpcs0SPRk_gpWDh","slug":"fastx402-lab-eip-55-ethereum-address-checksum-3955c975","name":"FastX402 Lab – EIP-55 Ethereum Address Checksum","description":"146 pay-per-call tools for AI agents, from $0.001 per request in USDC on Base or Solana with x402. No account, no API key.","url":"https://fastx402.tools/eth-checksum?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$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":["address"],"properties":{"address":{"type":"string","description":"EVM address, 0x + 40 hex characters"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"input":{"type":"string"},"address":{"type":"string"},"checksum_valid":{"type":"boolean"}}}}}}},"responseSchema":{"type":"json","example":{"input":"0xfb6916095ca1df60bb79ce92ce3ea74c37c5d359","address":"0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359","checksum_valid":true}},"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_mbGRDzJslEHxPJrrVcOGH","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":"Returns the EIP-55 checksummed form of an Ethereum/EVM address and validates whether the given casing is a correct checksum","exampleAgentPrompt":"Can you give me the EIP-55 checksummed version of this Ethereum address and tell me if the casing I have is valid: 0xfb6916095ca1df60bb79ce92ce3ea74c37c5d359?","exampleUseCases":[{"title":"Pre-transfer address verification","prompt":"Before I send ETH to 0xfb6916095ca1df60bb79ce92ce3ea74c37c5d359, can you checksum that address and confirm whether the casing is correct?"},{"title":"Normalizing a user-submitted wallet address","prompt":"A user just submitted 0xABCDEF1234567890abcdef1234567890ABCDEF12 as their wallet address — can you normalize it to its EIP-55 checksummed form so I can store it safely?"},{"title":"Validating a pasted address from a form","prompt":"I copied this address from a web form: 0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe — is the checksum valid, and what's the correct checksummed version?"}],"resultDescription":"A JSON object containing the original input address, the EIP-55 checksummed form of the address (with correct mixed-case hex), and a boolean indicating whether the input casing was already a valid EIP-55 checksum.","failureModes":["Invalid address format (not 0x + 40 hex chars) returns an error","Missing required 'address' query parameter returns a 400-level error","Non-hex characters in address body cause validation failure","Address shorter or longer than 42 characters is rejected"],"whenToPreferThis":"Use this endpoint when an agent needs to validate or normalize an Ethereum/EVM address before any operation involving funds transfer, smart contract interaction, or persistent storage — especially when the address was received from user input, a form, or an external source where typos or incorrect casing are possible. Prefer this over a local checksum library when operating in a serverless or constrained environment where crypto libraries aren't available, or when you want a pay-per-use approach with no SDK dependencies.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-17T12:39:11.026Z","isFirstParty":false,"canonicalSlug":"fastx402-lab-eip-55-ethereum-address-checksum-3955c975"}