ICS 23 is an open-source project aimed at establishing a universal, cross-language binary format for Merkle proofs, facilitating wide compatibility across different Merkle tree storage implementations and client libraries. Its primary objective is to standardize light-client proofs of blockchains, particularly those supporting IBC (Inter-Blockchain Communication) packets, as specified by the Cosmos ecosystem. Key features include proofs of existence and non-existence of key-value pairs linked to a root hash, with plans for future enhancements like batch proofs. The project is structured to deliver language-agnostic documentation and protobuf specifications, supporting client-side proof validation in languages such as Go and Rust while maintaining server-side logic with respective Merkle tree implementations. Although unsupported by some Merkle store formats like Ethereum’s Patricia Trie, ICS 23 emphasizes a configuration-oriented approach to accommodate diverse data sources, aiming to minimize custom client-side code dependencies.