Unconfirmed Transaction
mempool · fees
A transaction seen by the network but not yet included in a block, so its confirmation count is zero.
1.definition
An unconfirmed transaction is pending in one or more node mempools. It has been broadcast, but miners or validators have not yet included it in a block accepted by the network.
2.handling
Confirmation reliability depends on fees, mempool policy, conflicts, and network rules such as RBF. Users may be able to raise the fee, use CPFP, rebroadcast, or wait for congestion to clear.
Related terms
Mempool
→A node’s local collection of valid transactions waiting to be included in a block.
blockchain · node
Replace By Fee (RBF)
→A mempool policy that can accept a conflicting unconfirmed transaction when the replacement satisfies fee and relay rules.
bitcoin · policy · fees
Zero Confirmation
→A transaction observed before any block has included it.
transaction · security
Confirmations
→How many blocks have been added starting with the block that includes a transaction.
security · blockchain
Help make this definition clearer. Suggest a correction.