An on-chain account that stores up to 256 pubkeys, enabling v0 transactions to reference accounts by 1-byte index instead of full 32-byte pubkeys. ALTs dramatically reduce transaction size when interacting with many accounts (e.g., DEX routing). ALTs must be created and populated in advance; entries become active after a slot delay.
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An on-chain account that stores up to 256 pubkeys, enabling v0 transactions to reference accounts by 1-byte index instead of full 32-byte pubkeys. ALTs dramatically reduce transaction size when interacting with many accounts (e.g., DEX routing). ALTs must be created and populated in advance; entries become active after a slot delay.
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Address Lookup Table (ALT) (address-lookup-table) Category: Programming Model Definition: An on-chain account that stores up to 256 pubkeys, enabling v0 transactions to reference accounts by 1-byte index instead of full 32-byte pubkeys. ALTs dramatically reduce transaction size when interacting with many accounts (e.g., DEX routing). ALTs must be created and populated in advance; entries become active after a slot delay. Aliases: ALT, LUT Related: Versioned Transaction, Transaction Size Limit
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A transaction format introduced with v0 that supports address lookup tables. Legacy transactions include all pubkeys inline (limited to ~35 accounts); v0 transactions reference ALTs to include up to 256 accounts while staying within the 1,232-byte limit. The version byte (0) precedes the message.
The maximum serialized size of a Solana transaction: 1,232 bytes, matching the IPv6 minimum MTU to ensure single-packet transmission. This limit constrains the number of accounts, instructions, and data per transaction. Address lookup tables (v0 transactions) help fit more accounts within this limit.
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A function that derives a PDA by iterating bump seeds from 255 down to 0 until finding a pubkey not on the Ed25519 curve. It returns (pubkey, bump). In Anchor, the #[account(seeds=[...], bump)] constraint calls this automatically. The corresponding create_program_address skips iteration and takes an explicit bump.
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A transaction format introduced with v0 that supports address lookup tables. Legacy transactions include all pubkeys inline (limited to ~35 accounts); v0 transactions reference ALTs to include up to 256 accounts while staying within the 1,232-byte limit. The version byte (0) precedes the message.
The maximum serialized size of a Solana transaction: 1,232 bytes, matching the IPv6 minimum MTU to ensure single-packet transmission. This limit constrains the number of accounts, instructions, and data per transaction. Address lookup tables (v0 transactions) help fit more accounts within this limit.
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The fundamental data storage unit on Solana. Every piece of state is stored in an account identified by a 32-byte public key. Accounts hold a lamport balance, an owner program, a data byte array (up to 10MB), and an executable flag. Only the owning program can modify an account's data, but anyone can credit lamports to it.
Executable code deployed on-chain, equivalent to a smart contract on other blockchains. Programs are stateless—they store no data themselves but read/write data in separate accounts they own. Programs are compiled to SBF bytecode and loaded via the BPF Loader. Every program has a unique Program ID (its account's public key).
A single operation within a transaction that invokes a program. An instruction specifies: (1) the program ID to call, (2) an array of account metas (pubkey, is_signer, is_writable), and (3) an opaque data byte array. Programs decode the instruction data to determine which operation to perform.
An atomic unit of execution containing one or more instructions, a recent blockhash, and one or more signatures. All instructions in a transaction execute sequentially and atomically—if any instruction fails, the entire transaction reverts. Transactions have a 1,232-byte size limit (matching IPv6 MTU) and a default 200,000 CU budget.