Glossary OS

Plain meaning

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A mechanism that replaces the short-lived recent blockhash in a transaction with a nonce value stored in a dedicated on-chain nonce account, allowing the transaction to remain valid indefinitely until it is used or the nonce is advanced. The nonce account stores the current nonce hash and an authority; the first instruction of any durable-nonce transaction must be AdvanceNonceAccount, which updates the nonce and invalidates the old one. Durable nonces are essential for workflows requiring offline signing, hardware security modules, or multi-party approval over extended time periods.

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Durable Nonce (durable-nonce)
Category: Network
Definition: A mechanism that replaces the short-lived recent blockhash in a transaction with a nonce value stored in a dedicated on-chain nonce account, allowing the transaction to remain valid indefinitely until it is used or the nonce is advanced. The nonce account stores the current nonce hash and an authority; the first instruction of any durable-nonce transaction must be AdvanceNonceAccount, which updates the nonce and invalidates the old one. Durable nonces are essential for workflows requiring offline signing, hardware security modules, or multi-party approval over extended time periods.
Related: Blockhash (Recent), Transaction, Offline Signing

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Concept graph

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Branch

Blockhash (Recent)

A 32-byte hash derived from the bank's state at a given slot, included in every Solana transaction to prove the transaction was created recently and to prevent replay attacks. A blockhash remains valid for approximately 150 slots (~60–90 seconds at normal slot times); transactions submitted with an expired blockhash are rejected outright. Clients must fetch a fresh blockhash before signing and ideally reuse it for as short a window as possible to maximize landing probability.

Open term

Branch

Transaction

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.

Instruction Signature

Open term

Branch

Offline Signing

The practice of signing a Solana transaction on an air-gapped or disconnected device and then broadcasting the signed transaction bytes from an online machine, used to protect private keys from network-exposed environments. Because standard Solana transactions embed a recent blockhash that expires in ~90 seconds, offline signing in practice requires durable nonces to give signers an unlimited preparation window. Offline signing is common in institutional custody, hardware wallet workflows, and high-security treasury management.

Open term

Next concepts to explore

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Network

Blockhash (Recent)

A 32-byte hash derived from the bank's state at a given slot, included in every Solana transaction to prove the transaction was created recently and to prevent replay attacks. A blockhash remains valid for approximately 150 slots (~60–90 seconds at normal slot times); transactions submitted with an expired blockhash are rejected outright. Clients must fetch a fresh blockhash before signing and ideally reuse it for as short a window as possible to maximize landing probability.

Open term

Programming Model

Transaction

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.

Open term

Network

Offline Signing

The practice of signing a Solana transaction on an air-gapped or disconnected device and then broadcasting the signed transaction bytes from an online machine, used to protect private keys from network-exposed environments. Because standard Solana transactions embed a recent blockhash that expires in ~90 seconds, offline signing in practice requires durable nonces to give signers an unlimited preparation window. Offline signing is common in institutional custody, hardware wallet workflows, and high-security treasury management.

Open term

Network

Epoch Schedule

The configuration that defines the length of an epoch in slots and governs how epoch boundaries are calculated on a Solana cluster. On mainnet-beta, each epoch is 432,000 slots (approximately 2-3 days at 400ms per slot). The epoch schedule determines when staking rewards are distributed, when stake activations and deactivations take effect, and when the leader schedule is recalculated. It is set at genesis and queryable via the getEpochSchedule RPC method.

Open term

Related terms

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Networkblockhash

Blockhash (Recent)

A 32-byte hash derived from the bank's state at a given slot, included in every Solana transaction to prove the transaction was created recently and to prevent replay attacks. A blockhash remains valid for approximately 150 slots (~60–90 seconds at normal slot times); transactions submitted with an expired blockhash are rejected outright. Clients must fetch a fresh blockhash before signing and ideally reuse it for as short a window as possible to maximize landing probability.

Open term

Programming Modeltransaction

Transaction

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.

Open term

Networkoffline-signing

Offline Signing

The practice of signing a Solana transaction on an air-gapped or disconnected device and then broadcasting the signed transaction bytes from an online machine, used to protect private keys from network-exposed environments. Because standard Solana transactions embed a recent blockhash that expires in ~90 seconds, offline signing in practice requires durable nonces to give signers an unlimited preparation window. Offline signing is common in institutional custody, hardware wallet workflows, and high-security treasury management.

Open term

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Network

Mainnet Beta

Solana's primary production cluster where real SOL and real economic activity occur; the "beta" designation reflects the network's ongoing protocol development despite being fully live since March 2020. It uses the same architecture as other clusters but with real validator stakes, live staking rewards, and permanent on-chain state. All production dApps, tokens, and NFTs exist on Mainnet Beta.

Open term

Network

Devnet

A persistent public Solana cluster intended for application development and testing, running the same software version as Mainnet Beta but with no real economic value. Devnet SOL can be freely airdropped via the CLI or faucet APIs, and the ledger may be reset periodically by Solana Labs. Developers use Devnet to test programs and integrations before deploying to Mainnet Beta.

Open term

Network

Testnet

A public Solana cluster used primarily by the Solana core team and validators to test new software releases, performance benchmarks, and network upgrades under real network conditions before they reach Mainnet Beta. Testnet SOL has no monetary value, and the ledger is reset more frequently than Devnet; it is less suitable for application development and more suited for validator operators validating their infrastructure.

Open term

Network

TPS (Transactions Per Second)

The rate at which a Solana cluster processes and commits transactions; Solana's theoretical maximum exceeds 65,000 TPS due to its parallel execution model, though real-world sustained throughput on Mainnet Beta typically ranges from 2,000–5,000 non-vote TPS under normal load. Vote transactions (used for consensus) make up a significant portion of all on-chain activity and are counted separately. High TPS is enabled by Proof of History timestamps, Sealevel parallel execution, and Gulf Stream mempool-less forwarding.

Open term