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A – C
Account meta
Metadata attached to each account key in a transaction message, indicating whether the account is a signer, writable, or read-only. The order of account metas must match the order of account keys.
Recent blockhash
A recent block hash included in the transaction message. Transactions referencing a blockhash that is too old are rejected — this limits replay windows.
Compute units (CU)
The measure of computational work a transaction consumes when executed. Programs that perform more work use more compute units. Transactions specify a compute unit limit and may set a compute unit price.
Confirmed (commitment level)
A commitment level indicating the block containing the transaction has received a supermajority of validator votes. Lower latency than finalized, with slightly higher reorg risk.
D – F
Fee payer
The account debited for transaction fees. Typically the first signer. Must hold enough SOL to cover base fee plus any priority fee.
Finalized (commitment level)
The highest common commitment level. Indicates the block is finalized and reorg is extremely unlikely. Recommended for high-value settlement reads.
Inner instruction
An instruction invoked by a program during execution of an outer instruction — visible in explorer "inner instructions" panels. Common in swaps and complex DeFi calls.
G – I
Instruction
A single command within a transaction telling a program which accounts to use and what data to process. A transaction may contain multiple instructions executed in order.
Instruction data
Byte payload passed to a program with an instruction. Layout is program-specific — explorers often show a decoded view when a program IDL is available.
L – P
Lamports
The smallest unit of SOL. Fees and balances are often displayed in SOL but calculated in lamports (1 SOL = 1,000,000,000 lamports).
Priority fee
An optional additional fee calculated as compute unit limit × compute unit price. Used to compete for inclusion during congestion. Appears separately from the base fee on receipts.
Processed (commitment level)
The lowest latency commitment. The node has seen the transaction in a block, but the block may not yet be voted on widely. Suitable for low-stakes UI updates only.
Program ID
The public key of the on-chain program an instruction invokes — for example the System Program, Token Program, or a custom deployed program.
R – Z
Signature
A cryptographic signature authorizing the transaction. The number of required signatures is declared in the message header. Multi-sig transactions include multiple signature slots.
Slot
A unit of time in Solana's leader schedule. Transactions are included in blocks associated with slots. Confirmation panels show the slot at which a transaction was processed.
Transaction message
The structured payload describing accounts, recent blockhash, and instructions — signed by required parties. Distinct from the full transaction, which wraps signatures around the message.