A simple program that validates a string of UTF-8 encoded characters. It can be used to record a string on-chain, stored in the instruction data of a successful transaction.
Solana's programming model and the definitions of the Solana terms used in this document are available at:
The Memo Program's source is available on github
The on-chain Memo Program is written in Rust and available on crates.io as spl-memo.
The Memo program attempts to UTF-8 decode the instruction data; if successfully decoded, the instruction is successful.