An Ethereum Improvement Proposal (EIP) is a design document that describes a new feature, standard or process for Ethereum. EIPs range from changes to the core protocol, such as how gas fees are calculated, to application standards such as token interfaces. Each has a number, an author and a status, and is published at eips.ethereum.org after review by volunteer editors.
The format and workflow are defined in EIP-1, first published in 2015 and modelled, like Bitcoin's process, on Python's enhancement proposals. Its Bitcoin counterpart is the Bitcoin Improvement Proposal. Application-level standards are called ERCs (Ethereum Requests for Comments), as in ERC-20; since 2023 they have been kept in a separate ERCs repository, while core changes remain EIPs. An EIP is only a specification: core changes take effect when client teams ship them in a network upgrade.
EIPs in plain terms
Imagine the building code for a city that has no single mayor. Anyone may propose a change, from the width of fire exits to the shape of electrical sockets, but they must write it up on a standard form so engineers can review it. Socket designs only matter to the manufacturers who choose to use them. Changes to the structural rules only count once the city's builders agree a date and all start building that way together.
EIPs are that form. ERCs are like socket standards that wallets and apps adopt one by one. Core EIPs are like structural rules, switched on for everyone at once in a scheduled upgrade.
Types and statuses
EIP-1 defines three types. Standards Track EIPs affect most or all Ethereum implementations and fall into four categories: Core (consensus changes needing a hard fork), Networking (peer-to-peer protocols), Interface (client APIs) and ERC (application standards). Meta EIPs describe processes around Ethereum, and Informational EIPs give guidance without proposing a feature.
Each EIP moves through a set of statuses:
- Idea. Discussed informally before a draft exists.
- Draft. Merged into the repository and open to change.
- Review. The author marks it ready for peer review.
- Last Call. A final review window before the proposal is fixed.
- Final. The standard is settled; only errata are accepted.
Three further statuses sit outside that path: Stagnant (inactive for six months or more), Withdrawn (abandoned by the author) and Living (meant to be updated continually, like EIP-1 itself).
From EIP to network upgrade
Core EIPs reach mainnet through Ethereum's regular network upgrades. Client developers discuss candidates on the public All Core Developers calls, choose a bundle for the next upgrade, implement it across independent execution and consensus clients, and run it on test networks such as Sepolia and Hoodi before setting a block or epoch for activation. Every node and staking validator must upgrade before that point. Recent bundles include Dencun (March 2024), Pectra (May 2025) and Fusaka (3 December 2025).
ERCs follow a looser path: once a standard is final, wallets, smart contract developers and exchanges adopt it if they find it useful.
Landmark EIPs and ERCs
- EIP-20. The fungible token interface behind thousands of tokens, usually written ERC-20.
- EIP-155 (2016). Added a chain ID to transaction signatures, giving automatic replay protection between Ethereum and other chains.
- EIP-721 and EIP-1155. The ERC-721 standard for non-fungible tokens and the multi-token ERC-1155 standard.
- EIP-1559 (London, August 2021). Replaced the first-price fee auction with a protocol-set base fee that is burned, plus an optional tip.
- EIP-3675 (the Merge, September 2022). Moved Ethereum from proof of work to proof of stake.
- EIP-4488 and EIP-4844. EIP-4488 proposed cheaper calldata to help layer-2 rollups; the community instead adopted EIP-4844, which introduced data "blobs" in the Dencun upgrade.
- ERC-4337. ERC-4337 introduced account abstraction through smart contract wallets without a consensus change.
Criticism and debate
The EIP process is open and well documented, but participants point to a gap between the formal process and real decision-making. Which core EIPs ship, and when, is decided by rough consensus among client teams and researchers, with significant influence from the Ethereum Foundation, rather than by any vote of ether holders or users. Supporters say this keeps technical quality high; critics see it as informal governance by a small group. Others note that the process can be slow: popular proposals have sat in Draft or Review for years, and some, like EIP-4488, are overtaken by better designs before they ship.
The most contested EIP decision was not a numbered proposal at all: the 2016 DAO hard fork, which split off Ethereum Classic (ETC) and remains the clearest example of social consensus overriding the original chain's history.