What are Ethereum Standards - EIPs, ERCs, RIPs, CAIPs

Common standards in blockchain technology, such as EIPs, are crucial for enhancing usability but can be challenging to grasp. Here’s a detailed look at the four main types of standards, two well-known and two relatively new:

1. Ethereum Improvement Proposals (EIPs)

EIPs propose changes to the Ethereum protocol, affecting the consensus mechanism. At a high level, they fall into two categories:

• RPC/Client software changes: These updates are to client software interacting with the Ethereum network and do not require hard forks.
• Protocol or consensus changes: These involve alterations to the Ethereum protocol itself and necessitate a hard fork, requiring all nodes to upgrade to maintain compatibility.

EIP types

At a more granular level, there are more EIP types and subtypes, depending on what they're aiming to change or enhance.

• Standard Track: Changes affecting most or all Ethereum implementations, including:
  • Core: Requires a consensus fork.
  • Networking: Improvements to network protocols.
  • Interface: Client API/RPC specifications and standards.
  • ERC: Application-level standards, like token standards (EIP-20). ERCs are essentially a subset of EIPs.
• Meta: Processes surrounding Ethereum, requiring community consensus . Examples include procedures, guidelines, changes to the decision-making process, and changes to the tools or environment used in Ethereum development.
• Informational: Provides guidelines or information without proposing new features.

EIP status terms

In addition to type classification, there's also a lifecycle categorization, from idea conception to full implementation.

• Idea: A pre-draft stage not tracked in the EIP repository.
• Draft: The first formally tracked stage of an EIP.
• Review: Ready for and requesting peer review.
• Last Call: The final review before moving to final status, typically lasting 14 days.
• Final: The EIP is in a final state and only updated for errata and clarifications.
• Stagnant: Inactive EIPs in Draft or Review stages for over six months.
• Withdrawn: The EIP has been retracted by the author(s) and cannot be resurrected.
• Living: Designed for continual updates without reaching finality, such as EIP-1.

Ethereum Improvement Proposals - official Ethereum page with EIPs
EIPs on GitHub - official repository of EIPs
EIP.directory - List of important EIPs, ERCs, RIPs, and CAIPs, with short comments on why they matter

2. Ethereum Request for Comments (ERCs)

ERCs facilitate coordination between applications at the application level, thus not requiring a hard fork. Examples include:

• ERC-20: A token standard.
• ERC-721: A standard for non-fungible tokens (NFTs).

ERCs on GitHub - official repository of ERCs

3. Rollup Improvement Proposals (RIPs)

RIPs are a newer standard introduced by rollups (Layer 2 solutions). These standards allow for rapid innovation without the lengthy process of EIPs/ERCs. RIPs typically do not require hard forks unless changes to sequencers or validators are proposed.

All RIPs are optional. RIPs are and will always remain optional standards for Rollups and participants in the larger EVM ecosystem. RIPs are not a governance process.

RIPs on GitHub - official repository of RIPs

4. Chain Agnostic Improvement Proposals (CAIPs)

CAIPs aim to establish common standards across multiple blockchains, especially focusing on wallet interoperability. These are at the application level and can now be referenced within EIPs and ERCs.

Chain Agnostic Improvement Proposals - official website of the Chain Agnostic Standards Alliance
CAIPs on GitHub - official repository of CAIPs

Conclusion

EIPs and ERCs are the most well-established standards, focusing on the Ethereum protocol and application-level coordination, respectively. Newer standards, such as RIPs and CAIPs, have emerged to address the needs of Layer 2 solutions and cross-chain interoperability.