On ETH, a nonce is incremented each time a user submits a txn to the mempool to ensure they are executed sequentially.
On SOL, there is no mempool and a user can submit multiple valid transactions that can be executed in parallel.
2/ Each system has its trade-offs but that is outside the scope of this thread.
SOL txns must also specify a recent blockhash which tells the validator when it was submitted. After 150 slots, the txn expires and is dropped by the validator. @jstrry jstarry.notion.site/Transaction-co…