What is EIP (Ethereum Improvement Proposal)?

The numbered document format used to propose changes to Ethereum, from core protocol upgrades to application standards.

Standards at the application layer carry the ERC label, which is why the main token standard is known as ERC-20 and comes from EIP-20. Proposals are public from draft stage, so coming changes can be read in advance. The numbering is chronological rather than meaningful: a low number means an early submission, not an important one.

The confusion worth clearing up is that an EIP is not a law and not a decision. It is a written proposal. Most never ship. What actually changes the network is client software implementing a proposal and node operators running it, which is a separate and slower process.

How it works

The process itself is defined in EIP-1, which sets out the categories and the status track (source: EIP-1).

Proposals fall into a few types. Core proposals change consensus rules and require a network upgrade. Networking and interface proposals change how clients talk to each other or to applications. ERCs are application-level conventions that need no protocol change at all, which is why anyone can deploy a token following ERC-20 without anybody's permission.

The status track runs from Draft, through Review and Last Call, to Final. A proposal can also be marked Stagnant if it goes quiet or Withdrawn by its author. Reaching Final means the specification is settled, and for a core proposal it also means it was included in a network upgrade.

Core proposals are bundled into named upgrades rather than shipped individually, so several EIPs activate together at a scheduled block or epoch. Reading which EIPs are in an upcoming upgrade is the reliable way to know what will change, because the upgrade name alone tells you nothing.

Example

The chain of numbers behind a routine wallet screen is a good illustration. EIP-20 defines how the token reports balances. EIP-1559 sets the base fee your wallet quotes. EIP-155 puts the chain identifier into the signature so a transaction signed for one network cannot be replayed on another. All three are Final, all three are implemented in every major client, and none of them required your agreement to affect you.

Why it matters when you buy

Whether an exchange or wallet supports a token often comes down to which standards it implements, and unusual standards are the most common reason a withdrawal form rejects an address or a token arrives invisible. Before moving an asset, check which standard it uses and whether both ends support it. Network characteristics are summarized at the chain pages.

Related terms

erc 20 — the fungible token standard, erc 721 — the non-fungible standard, eip 1559 — the fee mechanism, eip 712 — readable signature requests, erc 4337 — smart-contract wallets, hard fork — how core proposals activate.

Questions

What is the difference between an EIP and an ERC?

An ERC is a category of EIP covering application-level standards, so every ERC is an EIP. The number is the same in both names, which is why EIP-20 and ERC-20 refer to one document.

Does an EIP number mean a change is coming?

No. Numbers are assigned when a draft is accepted into the repository, and most drafts never reach Final. Check the proposal's status before treating it as forthcoming.

Who decides which EIPs ship?

Client development teams and the wider community reach rough consensus through public calls, and node operators decide by choosing which software to run. There is no vote and no single authority.