ERC-20 tokens are fungible tokens on Ethereum that all implement the same six-function interface, which is why any ERC-20-compliant token works automatically with any ERC-20-aware wallet or exchange. Fabian Vogelsteller and Vitalik Buterin formalized the standard as EIP-20 on 19 November 2015. USDC, the largest regulated stablecoin, is an ERC-20 contract with $73.8 billion in circulation as of 17 September 2026 and native issuance on 38 blockchains. ERC-20 is also the foundation for a wider family of Ethereum standards, including ERC-721, ERC-1155, and ERC-4337, that extend the same interface-first model to NFTs, multi-token contracts, and smart wallets.
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This article explains what ERC-20 tokens are and how their interface works, then broadens into the rest of the ERC standard family, how new ERCs move from idea to Final status, and how ERC-20 shapes stablecoin infrastructure and cross-chain protocols in 2026.
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ERC-20 tokens are fungible Ethereum tokens where every unit is identical and interchangeable, defined by a published interface any contract can implement. One USDC is worth exactly the same as any other USDC; there is no unique ID or ownership record per unit, unlike an NFT. ERC-20 is the standard nearly all DeFi tokens and major stablecoins use.
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The ERC-20 specification, authored by Fabian Vogelsteller and Vitalik Buterin and created on 19 November 2015, reached Final status and now defines six mandatory functions and two events: transfer and transferFrom handle movement; approve and allowance handle delegation to a third-party spender; totalSupply and balanceOf handle state queries; and the Transfer and Approval events let wallets and explorers track activity without querying the contract directly.
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Any contract that exposes those six functions is ERC-20-compliant and interoperable with every ERC-20-aware wallet, exchange, and DeFi protocol without custom integration work. USDC, USDT, DAI, and the large majority of DeFi protocol tokens are ERC-20 contracts. Circle's USDC page reports $73.8 billion in circulation and native issuance on 38 blockchain networks as of mid-September 2026, all as ERC-20 (or ERC-20-equivalent) contracts on their respective chains. How ERC-20 tokens work covers the full interface breakdown in more depth.
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An ERC-20 token works by tracking balances and allowances in the contract's own storage and updating them only through the six standard functions. A wallet calls balanceOf to display a holding; a transfer calls transfer, which updates both parties' balances and fires a Transfer event that block explorers and portfolio trackers read.
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The approve and transferFrom pair is what lets DeFi protocols move tokens on a user's behalf. A user calls approve to authorize a spender, such as a Uniswap router, to move up to a set amount; the router then calls transferFrom when the swap executes. This two-step delegation model is why every DeFi swap, lend, or stake action on an ERC-20 token starts with an approval transaction before the action itself. Because ERC-20 is a convention rather than a protocol change, adding a new ERC-20 token to Ethereum requires no upgrade or coordination with node operators, only a contract deployment that implements the interface correctly.
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Beyond ERC-20, the ERC track defines interfaces for non-fungible tokens, multi-token contracts, smart wallets, and cross-chain intents. Each ERC is an application-layer specification published through the same EIP process, letting Ethereum's protocol layer stay stable while wallets, tokens, and dapps standardize independently on top of it.
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The ERC category sits inside the broader EIP framework at Ethereum Foundation (eips). Every ERC has a unique number (ERC-20, ERC-721, ERC-4337) and a status that moves through Draft, Review, Last Call, and Final. The "Request for Comment" name is borrowed from the IETF's RFC process, the same model that standardized HTTP and TCP/IP, adapted for permissionless onchain contracts.
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ERCs matter because Ethereum has no central authority that enforces contract interfaces. A wallet does not know how to display a token balance or an NFT unless the contract implements the exact functions the wallet expects. Once a standard reaches Final status, any project can build against it with confidence that every compliant contract speaks the same interface.
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An Ethereum ERC moves from idea to Final status through a community-run proposal process on GitHub, not a vote or a company decision. An author drafts a plain-text specification, the EIP editors assign it a number, and the proposal advances through Draft, Review, and a 14-day Last Call before reaching Final, provided no blocking objections surface.
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An Ethereum Improvement Proposal starts as a plain-text document submitted to the EIPs GitHub repository. For application-layer ideas, the type is "Standards Track, ERC." The author proposes a problem, specifies an interface, provides a reference implementation, and opens a pull request. After the EIP editors accept the format, the proposal is assigned a number and enters Draft status.
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From Draft, a proposal moves to Review when the author believes the spec is complete and invites broad feedback. Community discussion happens on the Ethereum Magicians forum, the primary venue where core developers, DeFi teams, and wallet builders debate proposed interfaces. A proposal enters Last Call when the editors judge that outstanding issues have been resolved. Last Call runs for 14 days. If no blocking objections arise during that window, the EIP moves to Final.
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Two terminal statuses also exist. Stagnant means the proposal has had no activity for 6 months or more; authors can revive it by updating the document. Withdrawn means the author has voluntarily retracted the proposal. Neither terminal status prevents a developer from implementing the spec informally. Market adoption sometimes precedes Final status entirely: ERC-4337 (account abstraction) was deployed at scale by teams including Alchemy, Stackup, and Biconomy while still in Draft.
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Anyone can submit an EIP. The barrier is quality of specification, not affiliation. Fabian Vogelsteller, who wrote ERC-20, was not a member of the Ethereum Foundation. William Entriken, the lead author of ERC-721, worked independently. The EIPs GitHub repository has accumulated thousands of proposals since 2015, with a small fraction reaching Final status, illustrating how much experimentation happens before community consensus forms.
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An EIP is the umbrella category for every proposed change to Ethereum. An ERC is the specific track within EIPs covering application-layer interfaces like ERC-20. EIPs touching consensus or the EVM affect every node; ERCs only affect contracts and wallets that choose to implement them. ERC-20 is technically EIP-20, but not every EIP is an ERC.
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The EIP framework divides proposals into three tracks. The Core track covers consensus and EVM changes, including EIP-1559 (the fee-burning mechanism introduced in August 2021) and EIP-4844 (proto-danksharding blobs, activated March 2024). The Networking track covers the p2p layer. The ERC track covers ABI specifications and application conventions shared across contracts and wallets, including ERC-20 itself.
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When a developer says "it's an ERC," they mean an application-layer standard with no protocol dependency. ERC-20 does not require any Ethereum upgrade; it is a convention. EIP-4844, by contrast, required a hard fork coordinated across all mainnet clients (Geth, Nethermind, Besu, Erigon). The governance paths differ: ERCs are approved by the EIP editors and community forum; Core EIPs require signoff from client teams, per the process described at ethereum.org/governance.
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Six ERCs define how most Ethereum application value moves, with ERC-20 as the foundation. ERC-20 standardized fungible tokens in 2015; ERC-721 created unique token identity in 2018; ERC-1155 handles both token types in one contract; ERC-4337 brought account abstraction to production without a consensus change; ERC-7715 defined granular wallet permissions; ERC-7683 specified a cross-chain intent format now used by multiple solver networks.
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These standards layer on each other. An ERC-4337 smart account wallet can hold ERC-20 tokens, receive ERC-721 NFTs, and accept ERC-7715 session permissions from a dapp, all within a single user context. The full ERC catalog at eips.ethereum.org lists every standard by number and status. The table below summarizes the key dimensions across the six major ERCs.
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ERC-721 is Ethereum's non-fungible token standard, giving each token a unique ID and owner record instead of the interchangeable balances ERC-20 uses. It was authored by William Entriken, Dieter Shirley, Jacob Evans, and Nastassia Sachs and created in January 2018. Uniswap V3 uses it to represent liquidity positions because each position is unique.
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ERC-721, authored by William Entriken, Dieter Shirley, Jacob Evans, and Nastassia Sachs and created in January 2018, adds a tokenId field to the token model. Each token has a unique ID, an owner address, and an ownerOf lookup. Uniqueness is enforced at the contract level: two calls to ownerOf(42) always return the same address until a transfer event changes it. CryptoPunks were retroactively wrapped to ERC-721 in 2021; Uniswap V3 uses ERC-721 to represent liquidity positions because each position carries unique fee-tier and range parameters.
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ERC-1155 lets a single contract manage both fungible and non-fungible token types together, replacing what used to require separate ERC-20 and ERC-721 deployments. Witek Radomski authored the standard, finalized in June 2019. It became the default choice for onchain gaming items and marketplace inventory because of its batch transfer functions.
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A single ERC-1155 contract can define token ID 1 as a fungible game currency (10 million units) and token ID 2 as a unique item (1 unit). Batch transfer functions reduce gas cost significantly when moving multiple token types at once. The ERC-1155 multi-token design became the default standard for onchain gaming item systems and marketplace inventory contracts.
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ERC-4337 lets smart contracts act as wallets and initiate transactions without any Ethereum protocol change, using a separate Bundler mempool. The EntryPoint contract went live on mainnet on 1 March 2023 and has facilitated over 26 million smart wallets and 170 million UserOperations, per ethereum.org's account abstraction roadmap.
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ERC-4337, authored by Vitalik Buterin, Yoav Weiss, Dror Tirosh, Shahaf Nacson, Alex Forshtat, Kristof Gazso, and Tjaden Hess, introduces a new transaction type called a UserOperation, processed by a separate Bundler mempool rather than the standard Ethereum mempool. Smart contract wallets submit UserOperations; bundlers aggregate them and pay gas; a singleton EntryPoint contract verifies and executes the batch. This removes the requirement for users to hold ETH for gas, since paymasters can sponsor fees in any ERC-20 token.
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ERC-7715 lets a wallet grant a dapp scoped, time-limited permissions instead of a fresh signature per transaction; ERC-7683 defines a shared order format so cross-chain solvers can fill the same intent regardless of which bridge they settle through. Both are still in Draft status but already used in production wallets and solver networks.
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A wallet implementing ERC-7715 can grant a DeFi protocol permission to execute trades up to $500 within a 24-hour window without asking for a fresh signature on every transaction. MetaMask's Delegation Toolkit and Coinbase Smart Wallet both reference ERC-7715 as a core primitive. The full ERC-7715 wallet permissions specification details the grant and revocation flow.
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A user signing an ERC-7683 order specifies input tokens, output tokens, and a fill deadline. Any solver network that reads the format can attempt fulfillment. Across Protocol and UniswapX both implemented ERC-7683-compatible order formats in 2024, creating a shared solver market rather than isolated liquidity pools per bridge. The shared intent standard is directly relevant to cross-chain intent protocols competing on fill speed and price.
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ERC-20 created the conditions for DeFi by giving every token a common interface, and related ERCs now extend that interoperability to smart wallets and cross-chain transfers. USDC alone carries $73.8 billion in circulation across 38 chains as an ERC-20 (or equivalent) contract, and protocols like Aave, Compound, and Curve treat ERC-20 stablecoins as interchangeable collateral because they all speak the same interface.
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Circle's Cross-Chain Transfer Protocol (CCTP), which enables native USDC burns on one chain and mints on another, treats USDC as an ERC-20 contract on every supported chain. The burn-and-mint mechanic is standardized: a contract calls burnLockedUSDC on the source chain, an attestation service confirms the burn, and a mintUSDC call on the destination chain creates the output. CCTP's cross-chain mechanics depend entirely on USDC remaining ERC-20-compliant; non-standard token contracts cannot use CCTP without a wrapper.
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ERC-4337 is reshaping how stablecoin payments work in practice. Smart contract wallets built on ERC-4337 can pay gas in USDC rather than ETH, execute recurring transfers without manual signing, and bundle multiple stablecoin moves into a single transaction. Platforms building stablecoin automation depend on ERC-4337's paymaster system to remove the ETH gas requirement for end users.
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ERC-7683's cross-chain intent standard is building toward a unified liquidity layer across chains. Rather than each bridge operating a proprietary order format, any solver watching the ERC-7683 order book can fill an intent regardless of which bridge they use to settle. Eco Routes selects among available settlement rails (including CCTP and Hyperlane) based on cost and finality, and the ERC-7683 intent format is a natural complement to how Eco's solver network evaluates and fulfills cross-chain stablecoin transfers. Eco supports 15 chains including Ethereum, Base, Optimism, Arbitrum, and Solana, the same chains where most ERC-7683 solver activity is concentrated.
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The compounding effect is significant. ERC-20 set the token interface; ERC-4337 enables smart wallets that hold those tokens without requiring ETH for gas; ERC-7683 gives those wallets a standardized way to express what they want across chains; and ERC-7715 lets dapps request time-limited permission to act on a user's behalf within those wallets. Each successive standard extended the system rather than replaced it. A protocol built today can support all four simultaneously using publicly available open-source implementations from projects like OpenZeppelin (ERC-20, ERC-721, ERC-1155) and Alchemy (ERC-4337).
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The canonical source for every Ethereum ERC standard, including ERC-20, is eips.ethereum.org, which renders the EIPs GitHub repository with status, authors, and full specification text. Ethereum Magicians hosts the discussion threads behind each proposal's design decisions.
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Each eips.ethereum.org page shows the current status, authors, discussion link, and full specification text. The raw GitHub files at github.com/ethereum/EIPs include motivation, specification, and rationale sections that explain why competing approaches were rejected, context the final spec text rarely repeats.
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For tracking new proposals and following live debates, Ethereum-magicians is the primary forum. Threads are indexed by EIP number. The multi-year debate around ERC-4337 versus alternative account-abstraction proposals (EIP-2938, EIP-3074) is archived there and provides context for why the final spec takes the shape it does.
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Developers integrating ERCs into production systems should monitor the Ethereum Magicians forum for breaking changes during Last Call periods. The spec can change materially between Draft and Last Call. ERC-4337's EntryPoint contract was redeployed at version 0.7 in April 2024 with breaking interface changes from v0.6, requiring migration for projects built against the earlier version. The trustless architecture that ERCs enable depends on interface stability after a standard reaches Final.
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USDC, USDT, and DAI are the most widely used ERC-20 tokens, alongside the large majority of DeFi governance and protocol tokens. USDC alone carries $73.8 billion in circulation as of 17 September 2026 and is natively issued on 38 blockchains, per Circle's transparency page. Any token implementing the six ERC-20 functions qualifies, regardless of its use case.
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ERC stands for Ethereum Request for Comment. It is the application-layer track within the Ethereum Improvement Proposal system. ERCs define shared interfaces for tokens, wallets, and smart contracts without modifying the Ethereum protocol itself. The name comes from the IETF's RFC process, which standardized TCP/IP and HTTP using the same open-comment model.
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ERC-20 is technically EIP-20. Every ERC shares its number with the broader EIP record, but belongs to the "Standards Track, ERC" category covering application-layer interfaces. Core EIPs (EIP-1559, EIP-4844) modify the Ethereum protocol and require client-team consensus across Geth, Nethermind, Besu, and Erigon. ERC-20 needed none of that; it required only community adoption.
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ERC-20 defines fungible tokens, where every unit is interchangeable: one USDC is identical to any other. ERC-721 defines non-fungible tokens, where each token has a unique ID and distinct ownership. A Uniswap V3 liquidity position uses ERC-721 because its fee tier and price range make it unique. The ERC-20 token guide covers the full interface breakdown.
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There is no fixed timeline. ERC-20 moved from draft to Final in roughly 2 years (2015 to 2017). ERC-4337 took over 2 years from initial proposal (2021) to Final (2023). Many proposals stall at Draft indefinitely. A proposal advances only when the authors resolve outstanding technical objections and the community reaches rough consensus on the Ethereum Magicians forum.
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Yes. ERC Final status is a community signal, not an enforcement mechanism. ERC-4337 smart account infrastructure was deployed on Ethereum mainnet in March 2023 and accumulated millions of user operations before the standard was finalized. Teams building on Draft ERCs accept interface-change risk: if the spec evolves before Final, deployed contracts may fall out of compliance with the finalized version.
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Sources and methodology. ERC status and author information verified against Ethereum Foundation (eips) in September 2026. USDC circulation and chain-count figures verified against Circle's USDC page on 21 September 2026. The ERC-4337 EntryPoint mainnet deployment date and cumulative smart-account figures come from the Ethereum Foundation's account abstraction roadmap page, linked inline. Statuses reflect the EIP repository at time of writing and change as proposals advance.
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