Glossary
EIP-1153 (Transient Storage)
An Ethereum upgrade (Dencun, 2024) that added TSTORE/TLOAD opcodes — per-transaction storage that costs ~100 gas per write and clears at the end of the transaction.
EIP-1153 introduced transient storage: a new storage region per contract that lives only for the duration of a transaction. TSTORE writes cost ~100 gas, dramatically cheaper than the 5,000–20,000 gas of SSTORE writes to persistent storage, and the values are automatically cleared at end of transaction.
The opcodes are useful for reentrancy guards, ephemeral state in multi-call execution, cross-contract communication within one transaction, and any pattern that used to abuse persistent storage for short-lived flags. Uniswap v4's hooks rely heavily on transient storage.