{"id":"ERC-55","name":"Mixed-case Address Checksum","status":"Final","chain":"both","category":{"id":"comprehension","name":"Comprehension & Display","description":"Making blockchain data readable to humans"},"journeyStages":[{"id":"authentication","name":"Authentication & Identity","description":"Proving who you are and logging in"}],"uxImpact":"Mixed-case addresses (0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed) catch typos before funds are lost — ~0.02% chance a random typo passes checksum. Design implications: always display checksummed addresses, validate checksum on paste/input with instant feedback, show clear error states for invalid checksums, consider case-preserving copy functionality. Design decisions: whether to auto-correct lowercase addresses or require exact match, how prominently to warn on checksum failure, whether to block or just warn on invalid checksums. Safety & Security Checklist rates verifying addresses with ERC-55 checksum as High priority — detects typos before sending.","hasDetailedContent":true,"content":{"id":"ERC-55","sources":[{"label":"Official specification","url":"https://eips.ethereum.org/EIPS/erc-55","type":"official-spec"}],"lastReviewed":"2026-05-25","lastUpdated":"2026-05-25","summary":"Mixed-case addresses (0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed) catch typos before funds are lost — ~0.02% chance a random typo passes checksum.","designerTakeaways":["You can always display checksummed addresses in your UI.","Your paste handler can validate checksum with instant feedback.","You can preserve exact casing on copy for power users."],"applicability":{"whenToUse":["Users paste or type addresses manually.","Wrong-address sends are irreversible.","Your app displays addresses anywhere."],"whenToAvoid":["Addresses come only from QR scan with embedded checksum.","Non-EVM address formats use different validation.","Read-only display with no user input."]},"prototypeFirst":[{"screen":"Primary happy path","why":"Prove the core user promise before edge cases.","covers":["Success state","Clear outcome copy"],"include":["Primary CTA","Confirmation feedback","Next step"]},{"screen":"Blocked or unsupported state","why":"Users discover limits when wallets or chains lack support.","covers":["Unsupported wallet","Wrong network"],"include":["Plain-language reason","Fallback action"]},{"screen":"Failure recovery","why":"Trust breaks when errors look like bugs.","covers":["User rejection","Transaction revert"],"include":["Retry path","Support context"]},{"screen":"Advanced disclosure","why":"Power users need technical detail without cluttering the default path.","covers":["Contract address","Token ID","Raw status"],"include":["Expandable section","Copy buttons","Explorer link"]}],"statesToDesign":[{"state":"Ready","trigger":"Prerequisites met.","userNeed":"Understand what happens next.","designResponse":"Enable primary action with plain-language preview."},{"state":"Awaiting signature","trigger":"Wallet prompt open.","userNeed":"Know what they are approving.","designResponse":"Mirror human-readable summary in app and wallet."},{"state":"Pending","trigger":"Transaction submitted.","userNeed":"Confidence it is progressing.","designResponse":"Show status strip with explorer link."},{"state":"Succeeded","trigger":"On-chain confirmation.","userNeed":"See updated ownership or balance.","designResponse":"Celebrate outcome and show new state clearly."},{"state":"Failed or reverted","trigger":"Validation or execution failed.","userNeed":"Fix or retry without guessing.","designResponse":"Name the failed constraint and offer a concrete next step."}],"designDecisions":[{"question":"How much protocol detail do users see?","recommendation":"Lead with outcomes; tuck identifiers behind review.","rationale":"Users decide on consequences, not function selectors."},{"question":"What happens when support is missing?","recommendation":"Block with explanation and fallback path.","rationale":"Silent failure feels like a broken product."},{"question":"How do you label restricted assets?","recommendation":"Use persistent badges for non-transferable, locked, or expiring states.","rationale":"Hidden restrictions cause rage-quits at transfer time."}],"problemsSolved":[{"problem":"Inconsistent behavior across apps","oldWay":"Each team reinvents copy and edge cases","newWay":"Shared standard gives predictable UX patterns","impact":"high"},{"problem":"Users surprised by on-chain rules","oldWay":"Generic transfer UI fails at submit time","newWay":"Standard-aware UI sets expectations upfront","impact":"high"},{"problem":"Support burden from opaque errors","oldWay":"Raw revert reasons in toasts","newWay":"Mapped states explain what to do next","impact":"medium"}],"uxPatterns":[{"name":"Instant Checksum Validation","description":"Validate on paste with clear error state.","mockup":"concept/verify-safety","components":["AddressInput","ChecksumValidator","ErrorInline"],"userFlow":["User pastes address","Checksum validated","Green check or red error","Send blocked on invalid"]},{"name":"Checksummed Display","description":"Always render proper mixed-case.","mockup":"concept/verify-safety","components":["ChecksummedText","CopyButton"],"userFlow":["Address loaded","Checksummed format applied","User copies valid format","Recipient apps validate successfully"]}],"seenInTheWild":[{"app":"MetaMask","url":"https://metamask.io/","note":"Validates checksum on send and warns on invalid addresses."},{"app":"Etherscan","url":"https://etherscan.io/","note":"Displays checksummed addresses on all pages."},{"app":"MyCrypto","url":"https://www.mycrypto.com/","note":"Early advocate for checksum validation in send flows."}],"antiPatterns":[{"pattern":"Hiding standard-imposed restrictions until submit","why":"Users feel tricked when actions fail at the last step","instead":"Show eligibility and badges before the primary CTA","severity":"critical"},{"pattern":"Protocol jargon in user-facing copy","why":"Non-technical users cannot consent informedly","instead":"Use outcome language with optional technical disclosure","severity":"high"},{"pattern":"No fallback when wallet lacks support","why":"Dead-end flows increase churn","instead":"Explain limitation and offer alternate path or network","severity":"high"}],"vocabulary":[{"use":"Your balance / Your item","avoid":"Token ID / Token contract","why":"Ownership language matches mental models."},{"use":"Cannot transfer yet","avoid":"Transfer reverted","why":"Explain restriction without EVM vocabulary."},{"use":"Confirm in wallet","avoid":"Sign transaction","why":"Matches wallet UX users already know."}],"onMonad":[{"aspect":"Confirmation speed","ethereum":"Multi-step flows can feel slow between signatures","monad":"Sub-second finality tightens feedback loops","designImplication":"Prefer inline status over long pending modals on Monad."},{"aspect":"Transaction cost","ethereum":"Gas can discourage exploratory actions","monad":"Lower fees enable lighter-weight interactions","designImplication":"Safe to offer preview retries and social actions more freely."}],"technicalNotes":"ERC-55 checksum uses mixed case; ~0.02% of random typos pass — still validate.","relatedStandards":[{"id":"EIP-1191","relationship":"Chain-specific checksum extension"},{"id":"ERC-7930","relationship":"Chain-aware address format complement"}]},"sources":[{"label":"Official specification","url":"https://eips.ethereum.org/EIPS/erc-55","type":"official-spec"},{"label":"Discussion","url":"https://ethereum-magicians.org/search?q=ERC-55","type":"discussion"},{"label":"Official specification","url":"https://eips.ethereum.org/EIPS/erc-55","type":"official-spec"}],"urls":{"canonical":"https://www.eipsfordesigners.com/standards/ERC-55","markdown":"https://www.eipsfordesigners.com/standards/ERC-55/content.md","agent":"https://www.eipsfordesigners.com/standards/ERC-55/agent.md","api":"https://www.eipsfordesigners.com/api/standards/ERC-55","official":"https://eips.ethereum.org/EIPS/erc-55","discussion":"https://ethereum-magicians.org/search?q=ERC-55"},"freshness":{"lastReviewed":"2026-05-25","lastUpdated":"2026-05-25"}}