Instructions

An instruction is a request to execute a specific function on a Solana program. Instructions are the fundamental building block for on-chain operations. Each instruction specifies exactly one program to call, the accounts it needs, and a byte array of data that the program interprets (typically a discriminator to identify which instruction handler to run, followed by serialized arguments). Execution logic for each instruction is stored on a program, where each program defines its own set of instructions. To interact with the Solana network, one or more instructions are added to a transaction and sent to the network to be processed.

Diagram depicting a transaction with an instruction, broken up into its 3 components

Key facts

• Single program: Each instruction targets exactly one program via program_id.
• Account metadata: The accounts array provides AccountMeta for every account the instruction reads or writes.
• Opaque data: The data field is a byte array whose format is defined by the target program.