In Solana, all state is stored in accounts. Anchor provides strongly-typed account wrappers that automatically handle validation and deserialization.
Account types Anchor provides several account types that handle common validation patterns:
Account<‘info, T> The most common account type that wraps a custom account type with automatic validation.
#[derive( Accounts )] pub struct UpdateData & lt ;' info & gt ; { #[account( mut )] pub my_account : Account <' info , MyAccount >, pub authority : Signer & lt ;' info & gt ;, } #[account] pub struct MyAccount { pub data : u64 , pub authority : Pubkey , }
The Account<'info, T> type automatically:
Deserializes the account data into type T
Checks the account owner matches the program ID
Validates the account discriminator matches type T
Signer<‘info> Verifies that an account signed the transaction.
#[derive( Accounts )] pub struct Initialize & lt ;' info & gt ; { #[account( mut )] pub authority : Signer & lt ;' info & gt ;, pub system_program : Program <' info , System >, }
The Signer type automatically checks that authority.is_signer is true.
SystemAccount<‘info> Represents a native Solana account owned by the System Program.
#[derive( Accounts )] pub struct TransferSol & lt ;' info & gt ; { #[account( mut )] pub from : SystemAccount & lt ;' info & gt ;, #[account( mut )] pub to : SystemAccount & lt ;' info & gt ;, }
Program type Verifies that an account is an executable program.
#[derive( Accounts )] pub struct Initialize & lt ;' info & gt ; { pub system_program : Program <' info , System >, pub token_program : Program <' info , Token >, }
The Program type checks that the account is executable.
UncheckedAccount<‘info> Raw AccountInfo with no automatic checks. Use with caution.
#[derive( Accounts )] pub struct Dangerous & lt ;' info & gt ; { /// CHECK: This is not dangerous because we don't read or write from this account pub unchecked : UncheckedAccount & lt ;' info & gt ;, }
Always add a /// CHECK: doc comment explaining why the account doesn’t need checks.
Interface types For Token-2022 compatibility, use interface types:
use anchor_spl :: token_interface :: { TokenAccount , Mint , TokenInterface }; #[derive( Accounts )] pub struct Transfer & lt ;' info & gt ; { #[account( mut )] pub from : InterfaceAccount <' info , TokenAccount >, #[account( mut )] pub to : InterfaceAccount <' info , TokenAccount >, pub token_program : Interface <' info , TokenInterface >, }
Account validation Anchor provides constraints for automatic account validation:
Initialization constraints #[derive( Accounts )] pub struct Initialize & lt ;' info & gt ; { #[account( init, payer = user, space = 8 + 32 + 8 )] pub my_account : Account <' info , MyAccount >, #[account( mut )] pub user : Signer & lt ;' info & gt ;, pub system_program : Program <' info , System >, }
Mutable accounts #[account( mut )] pub my_account : Account <' info , MyAccount >,
Field validation #[derive( Accounts )] pub struct Update & lt ;' info & gt ; { #[account( mut , has_one = authority, constraint = my_account . count < 100 )] pub my_account : Account <' info , MyAccount >, pub authority : Signer & lt ;' info & gt ;, }
The has_one = authority constraint checks that my_account.authority == authority.key().
PDA validation #[derive( Accounts )] pub struct Initialize & lt ;' info & gt ; { #[account( init, payer = user, space = 8 + 32, seeds = [ b"vault" , user . key() . as_ref()], bump )] pub vault : Account <' info , Vault >, #[account( mut )] pub user : Signer & lt ;' info & gt ;, pub system_program : Program <' info , System >, }
Accessing account data Access account fields directly through the validated account:
pub fn update ( ctx : Context < Update >, new_value : u64 ) -> Result <()> { let account = & mut ctx . accounts . my_account; account . data = new_value ; account . authority = ctx . accounts . authority . key (); Ok (()) }
Account lifetime The 'info lifetime indicates that account references are valid for the duration of the instruction:
#[derive( Accounts )] pub struct MyAccounts & lt ;' info & gt ; { pub account : Account <' info , MyAccount >, }
This ensures accounts can’t be used after the instruction completes.
Complete example use anchor_lang :: prelude ::* ; declare_id! ( "Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS" ); #[program] pub mod accounts_example { use super ::* ; pub fn initialize ( ctx : Context < Initialize >, data : u64 ) -> Result <()> { let account = & mut ctx . accounts . my_account; account . data = data ; account . authority = ctx . accounts . authority . key (); msg! ( "Account initialized with data: {}" , data ); Ok (()) } pub fn update ( ctx : Context < Update >, new_data : u64 ) -> Result <()> { let account = & mut ctx . accounts . my_account; require! ( account . authority == ctx . accounts . authority . key (), ErrorCode :: Unauthorized ); account . data = new_data ; msg! ( "Account updated to: {}" , new_data ); Ok (()) } } #[derive( Accounts )] pub struct Initialize & lt ;' info & gt ; { #[account( init, payer = authority, space = 8 + 8 + 32 )] pub my_account : Account <' info , MyAccount >, #[account( mut )] pub authority : Signer & lt ;' info & gt ;, pub system_program : Program <' info , System >, } #[derive( Accounts )] pub struct Update & lt ;' info & gt ; { #[account( mut , has_one = authority )] pub my_account : Account <' info , MyAccount >, pub authority : Signer & lt ;' info & gt ;, } #[account] pub struct MyAccount { pub data : u64 , pub authority : Pubkey , } #[error_code] pub enum ErrorCode { #[msg( "You are not authorized to perform this action" )] Unauthorized , }
Next steps
Account constraints Complete reference of all account constraints
PDAs Learn about Program Derived Addresses