Mempool is a website for checking the block and transaction memory pool of the Bitcoin network. It is very useful for checking the on-chain handling fees and on-chain congestion in daily life.

Here is a brief introduction to the meanings of several panels on the homepage (with pictures):

mempool 1-1
mempool 1-2

1. Confirmed blocks. There is a serial number, indicating that it is the xth block on the chain.

2. Unconfirmed blocks.

3. Overview of block contents. From top to bottom:

  • 3.1 Median Fee Rate

  • 3.2 Fee Rate Range

  • 3.3 Total block transaction fees (in addition to this, miners also receive block rewards, currently 3.125 BTC)

  • 3.4 Number of transactions in a block

  • 3.5 How long ago was the block?

4. The fee priority of the next block. Daily on-chain transactions mainly use this to determine how much transaction fee you need to pay. No Priority refers to the smaller value of Low Priority and the minimum fee*2. (The minimum fee will be mentioned below)

5. Difficulty level.

6. Overview of transactions in the block. There are three main filter options here (you can actually filter more by clicking in)

  • 6.1 Consolidation: Consolidation operation (many addresses are consolidated into one address, usually done by exchanges)

  • 6.2 Coionjoin: Mixing coins. Multiple inputs, multiple outputs

  • 6.3 Data: Some data operations, such as inscriptions and Runes

7. Memory pool situation. Purging indicates the lowest fee rate. The default memory pool of a node is 300MB. Some transactions with low handling fees will be directly rejected to prevent wasting space.

8. The most recent additional fee replacement operation. RBF (Replace-By-Fee) means replacing the previous transaction with a higher fee. FULL RBF means that some nodes support RBF operations even when the transaction does not have the RBF flag set.

9. Recent transactions.