Back to Learn
storage
Storage Data Types
Understand the storage-specific types for persisting data on-chain.
Storage Data Types
Stylus provides special storage types for on-chain persistence. These are different from regular Rust types.
Basic Storage Types
- StorageU256 - Stores unsigned 256-bit integers
- StorageI256 - Stores signed 256-bit integers
- StorageBool - Stores boolean values
- StorageAddress - Stores Ethereum addresses
- StorageString - Stores dynamic strings
Storage Maps
StorageMap provides key-value storage:
``rust
balances: StorageMap
Storage Vectors
for dynamic arrays:`rust
items: StorageVec,
`Access Methods
All storage types use:
-
- Read the value
-
.set(value) - Write a value
- StorageString uses
.get_string() and .set_string()`Code Example
use stylus_sdk::prelude::*;
use stylus_sdk::storage::{
StorageU256, StorageBool, StorageAddress,
StorageString, StorageMap, StorageVec
};
use alloy_primitives::{Address, U256};
#[storage]
pub struct MyContract {
// Basic types
count: StorageU256,
is_active: StorageBool,
owner: StorageAddress,
name: StorageString,
// Collections
balances: StorageMap<Address, U256>,
items: StorageVec<U256>,
}
#[public]
impl MyContract {
pub fn get_count(&self) -> U256 {
self.count.get()
}
pub fn set_count(&mut self, value: U256) {
self.count.set(value);
}
pub fn get_balance(&self, addr: Address) -> U256 {
self.balances.get(addr)
}
pub fn set_balance(&mut self, addr: Address, amount: U256) {
self.balances.insert(addr, amount);
}
}