Lifecycle of a transaction
You build a transaction, the wallet signs it, an RPC node broadcasts it, validators include it in a block, and then confirmations accumulate. Until it is included it lives in the mempool (or leader queue on Solana).
- •Pending: broadcast, not yet in a block.
- •Included: in a block, 1 confirmation.
- •Finalised: economically irreversible (chain-specific depth).
Ordering: nonces vs UTXOs vs blockhash
EVM accounts use an incrementing nonce, so transaction #5 cannot land before #4. Bitcoin and Dogecoin spend specific UTXOs, so double-spends conflict at the input level. Solana transactions embed a recent blockhash and expire after ~150 slots.
What you pay
EVM charges gas units × gas price (base fee + priority tip, EIP-1559). Solana charges a tiny fixed lamport fee per signature plus an optional priority fee per compute unit. UTXO chains charge by transaction size in sats/vByte.