Key Limitation: A Single UTXO Can Only Be Spent Once
- A contract on Nexa is bound to a single UTXO. Once you spend it, that UTXO vanishes, replaced by new UTXOs.
- Concurrency in the sense “User A and B both call the same UTXO at the same time” leads to a double-spend conflict.
- Whichever transaction is confirmed first “wins”; the other becomes invalid.
Hence, you cannot have multiple separate transactions simultaneously updating the same “internal” variable from the same UTXO.
What are the ways to handle multiple users concurrent interactions with a contract like an account based chain (EVM) ? if sharing in multiple UTXO : how to shard and handle the logic on a common variable ?