State Invariants

State Invariants are conditions related to the internal data storage of a contract that must always be valid. For example, in a decentralized exchange, the invariant might be that the product of the two token reserves must remain constant during a trade.

These invariants define the economic rules of the system and prevent users from draining liquidity or manipulating prices. Automated proving tools use these state invariants to verify that the contract's storage is updated correctly.

They are the most important constraints to define when building financial protocols. If a state invariant is violated, the system is fundamentally broken.

By enforcing these rules at the code level, developers ensure the long-term solvency of their platform. They are the bedrock of reliable financial engineering on the blockchain.