On-chain basics

Network congestion

Congestion is when transaction demand exceeds block capacity, pushing fees up and confirmation times out.

Typical during market volatility or NFT/memecoin frenzies. Fee estimators lag, so transactions sent with yesterday’s fee can stall.

On Swap.bz

Swap.bz publishes typical times, not guarantees, precisely because congestion is outside anyone’s control.

Mempool

The mempool is the waiting room of unconfirmed transactions on a node; miners pick the highest-fee ones first.

Network fee

The network fee is what the blockchain charges to include a transaction — paid to miners or validators, not to the exchange.

← All 62 terms · Last reviewed 2026-09-06