Approving & Permissioning

Permit Extension for ERC-20

Token approvals via signature instead of transaction — users sign a message, relayer submits on-chain, no ETH needed for approval step. Design implications: replace 'Approve' transaction with signature request, show 'gasless approval' badge, display permit expiry/deadline clearly, warn about permit phishing (malicious sites requesting signatures). Design decisions: tradeoff between convenience (longer deadlines) and security (shorter expiry), must educate users that signatures can be dangerous, consider revoking stale permits in UI. Live for USDC, DAI, UNI, and aTokens but not universal. Addresses Redundant Token Approvals pain point (High severity) — separate approval is where most first-time DeFi users abandon.

Category: Transaction Friction

Rental NFT

NFTs have separate 'owner' and 'user' roles with automatic expiration — enabling trustless rentals. Design implications: display dual ownership badges (Owner vs User), show rental expiration countdown timers, design rental listing flows with duration pickers, indicate 'rented out' status on owned items, auto-update UI when rental expires without transaction. Design decisions: how prominently to show rental status vs ownership, whether to notify users before rental expiry, handling edge cases where user tries owner-only actions.

Category: NFT Capabilities

Rental NFT for ERC-1155

Rental system for ERC-1155 tokens with quantity-based user records and expiration. Design implications: show 'usable balance' vs 'frozen balance' separately, display rental records with amount/expiry per record, enable partial quantity rentals, design rental management dashboards showing multiple active rentals. Design decisions: how to visualize frozen vs usable tokens in inventory, complexity of supporting multiple concurrent rental records, whether to auto-consolidate expired records.

Category: NFT Capabilities

ERC-721 Nonce Extension

NFTs have nonces that change on transfer — prevents reactivation attacks where old marketplace listings become valid again. Design implications: show listing validity warnings ('This listing may be stale'), auto-cancel orders when nonce changes detected, indicate when an NFT was recently transferred. Design decisions: tradeoff between surfacing technical details (nonces) vs abstracting them, must decide how prominently to warn about potentially dangerous legacy listings on non-5008 NFTs.

Category: Transaction Friction

Minimal Soulbound NFTs

Tokens marked as 'locked' cannot be transferred — minimal soulbound implementation for credentials, memberships, achievements. Design implications: show 'Soulbound' or 'Non-transferable' badge, hide/disable transfer buttons, explain permanence clearly. Design decisions: whether to show soulbound tokens in trading contexts at all — filter out or display with clear 'Not for Sale' status.

Category: Identity & Privacy

ERC-1155 Allowance Extension

ERC-1155 tokens get granular approvals by ID and amount — no more 'approve all' for semi-fungible tokens. Design implications: design per-token-ID approval selectors, show approved quantities remaining, enable approval management dashboards for 1155 holdings. Design decisions: more control means more UI complexity — decide granularity of approval controls (per-ID, per-amount, or simplified presets), balance security benefits against approval fatigue for users with many token types.

Category: Transaction Friction

Endorsement (Generalized Permit)

Generalized permit system — any function can accept off-chain signatures for authorization, enabling multi-sig and threshold signing in one transaction. Design implications: design multi-party approval collection UI, show endorsement status ('2 of 3 signed'), enable off-chain voting/approval workflows. Design decisions: complex signature coordination UX — must make gathering multiple signatures intuitive, handle partial endorsement states, decide how to display endorser identities and validity windows.

Category: Transaction Friction

Consensual Soulbound Tokens

Soulbound tokens require recipient consent before minting and have predetermined burn rules (issuer-only, owner-only, both, neither). Design implications: show consent flow before accepting SBT, display burn authority clearly, add 'Request Burn' action where applicable. Design decisions: how to present burn authority — affects user understanding of permanence, recovery options if keys lost.

Category: Identity & Privacy

Multi-privilege Management NFT

NFTs carry multiple transferable privileges (discounts, access, votes) that can be shared or assigned separately from ownership. Design implications: show privilege list with individual expiry dates, add 'Share Privilege' action, display privilege holder vs token owner. Design decisions: how to visualize privilege spreading/cloning — referral tree view, privilege inheritance tracking, balance utility discovery with UI complexity.

Category: Security & Trust

Non-Fungible Token Roles

Multiple custom roles (not just user/owner) can be assigned to NFTs with expiration and custom data. Design implications: display role badges per NFT (e.g., 'Manager', 'Tenant', 'Beneficiary'), show role assignment/revocation flows, visualize role hierarchies and permissions, design role marketplace for granting/revoking. Design decisions: how many roles to display before truncating, whether to show technical role IDs or friendly names, complexity of multi-role management UI vs simplified views.

Category: NFT Capabilities

Session Keys

Users pre-authorize a scope of actions so they don't sign every interaction — 'approve once, interact freely' for gaming, trading, and social apps. Design implications: design session key creation flows with clear scope display (which actions, spending limits, duration), show active session indicators, add session revocation UI, display remaining session budget/time. Design decisions: balance between permissiveness (fewer prompts) and security (tighter scopes), how to visualize session boundaries to users, whether to auto-expire sessions or require manual revocation. Primary solution to Signing Fatigue (High severity). MetaMask Delegation Toolkit and Viem implementing.

Category: Transaction Friction

Clear Signing Metadata

Builds on EIP-712 to provide full human-readable transaction summaries — transforms 'sign this hex blob' into 'Send 100 USDC to vitalik.eth.' Design implications: display complete transaction summaries in plain language, show contract interaction details (function name, parameters) in human terms, enable 'Domain verified on-chain' indicators, integrate with transaction simulation for balance change previews. Design decisions: how to handle contracts without clear signing metadata (fallback to raw data vs blocking), trust model for metadata providers, how prominently to warn when clear signing data is unavailable. Critical priority across 5+ pain points (blind signing, blanket warnings, scam prevention). The standard that powers the clear-signing movement (clear-signing.org).

Category: Comprehension & Display

Access Control Registry

Centralized registry manages roles across multiple contracts — admins grant/revoke permissions from single dashboard. Design implications: build unified permission management UI, show role assignments across contracts, display audit trail of permission changes. Design decisions: how granular to make role visibility — show all roles or just relevant ones, balance admin power with principle of least privilege.

Category: Security & Trust