EIP-2612: ERC-20 Permit Extension
EIP-2612 is how DEXes, lending protocols, and meta-tx relayers achieve gasless approvals. If you're integrating ERC-20s into any UX where the user shouldn't need ETH first, permit() is the canonical solution. DAI, USDC, and most modern stablecoins implement it.
What It Defines
Adds a permit(owner, spender, value, deadline, v, r, s) function to ERC-20 tokens, letting holders authorize allowances via an EIP-712 signature instead of an on-chain approve() transaction. Eliminates the classic two-transaction approve+transferFrom dance and the $0 gas problem when a user has tokens but no ETH. Each token tracks a per-owner nonce to prevent replay.
Canonical (Normative)
Convenient (Practical)
The Ethereum community's open process for proposing changes to the protocol. EIPs cover core protocol changes; ERCs (Ethereum Request for Comments) cover application-layer standards like token interfaces.
Related Specs
ERC-20 is the most widely deployed standard in the Ethereum ecosystem. Every DeFi integration, exchange, and wallet interacts with ERC-20 tokens constantly.
EIP-712 is the standard for secure off-chain message signing used in permit() flows, meta-transactions, and Sign-In with Ethereum. Prevents blind signing attacks.
EIP-3009 is the gasless transfer primitive USDC uses on Ethereum and Base. It's the on-chain mechanism behind the x402 "exact" scheme: the buyer signs an authorization, the seller (or facilitator) submits it on-chain to settle. If you're building anything that spends USDC on behalf of a user without them paying gas, this is the spec.
x402 is the leading candidate for the agent-economy payment rail: it lets an AI agent (or any HTTP client) pay for an API call inline, with no API key, no signup, and no human-in-the-loop. If you're building agentic apps, paid MCP servers, per-request data products, or anything where "charge for this request without a session" matters, x402 is the standard to know — supported by Coinbase, Cloudflare, Vercel AI Gateway, and a growing facilitator ecosystem.