An 8-byte identifier prepended to account data and instruction data to distinguish types. Anchor computes it as the first 8 bytes of `sha256('account:<AccountName>')` for accounts and `sha256('global:<function_name>')` for instructions. Discriminators prevent type cosplay attacks by ensuring data is deserialized as the correct type.
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An 8-byte identifier prepended to account data and instruction data to distinguish types. Anchor computes it as the first 8 bytes of `sha256('account:<AccountName>')` for accounts and `sha256('global:<function_name>')` for instructions. Discriminators prevent type cosplay attacks by ensuring data is deserialized as the correct type.
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Think of it as one of the core moving pieces your program reads, writes, or invokes at runtime.
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Accounts, instructions, PDAs, transactions, and execution flow.
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Discriminator (discriminator)
Category: Programming Model
Definition: An 8-byte identifier prepended to account data and instruction data to distinguish types. Anchor computes it as the first 8 bytes of `sha256('account:<AccountName>')` for accounts and `sha256('global:<function_name>')` for instructions. Discriminators prevent type cosplay attacks by ensuring data is deserialized as the correct type.
Related: Anchor Framework, Instruction, Account DataUse glossary context, relationships, mental models, and builder paths to get structured answers instead of generic chat output.
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The most popular framework for building Solana programs in Rust. Anchor provides macros (#[program], #[account], #[derive(Accounts)]) that auto-generate boilerplate for account validation, serialization, discriminators, and error handling. It includes a CLI (anchor init/build/test/deploy), IDL generation, and TypeScript client generation. Reduces program code by ~80% compared to native development.
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.
The byte array stored in an account that holds program-specific state. Data is typically serialized using Borsh and must be explicitly allocated at account creation. The maximum data size is 10MB. Programs are responsible for defining and managing their own data layout, including discriminators for type identification.
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The most popular framework for building Solana programs in Rust. Anchor provides macros (#[program], #[account], #[derive(Accounts)]) that auto-generate boilerplate for account validation, serialization, discriminators, and error handling. It includes a CLI (anchor init/build/test/deploy), IDL generation, and TypeScript client generation. Reduces program code by ~80% compared to native development.
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.
The byte array stored in an account that holds program-specific state. Data is typically serialized using Borsh and must be explicitly allocated at account creation. The maximum data size is 10MB. Programs are responsible for defining and managing their own data layout, including discriminators for type identification.
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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.