Mempool, also known as the memory pool, transaction pool or txpool, is a dynamic, in-memory space for transactions awaiting block inclusion. Rather than a single, unified pool, each node maintains its own transaction pool, collectively constituting the global memory. This constantly changing dataset, containing thousands of pending transactions, represents millions of dollars in flux at any given moment.

Mempool configurations vary wildly across different protocols & node client configurations.

The table here is a maintained reference of mempool configurations & specifics across all the protocols that Chainstack supports.

The table structure:

Protocol — protocol name.
Protocol availability — details of the mempool availability on the protocol level.
Chainstack availability — how to access the protocol's mempool on Chainstack.
Client configuration — the default node client configuration for the mempool as deployed at Chainstack.
Example — a simple curl example. Remember to replace YOUR_CHAINSTACK_NODE with your Chainstack node endpoint for that particular protocol.

Remember that whatever the default configuration, we can always customize it for you on a dedicated node 💙🛠️.

Protocol	Protocol availability	Chainstack availability	Client configuration	Example
Ethereum	Available to everyone	Archive with Debug and trace APIs	4096 pending transactions	Ethereum txpool_content
Polygon	Available to everyone	Archive with Debug and trace APIs	4096 pending transactions	Polygon txpool_content
BNB Smart Chain	Available to everyone	Archive with Debug and trace APIs	4096 pending transactions	BSC txpool_content
Base	Private to Sequencer.	N/A	N/A	N/A
Avalanche	Available only to validators.	Not available on Chainstack	N/A	N/A
TON	External messages are available in mempool	Available
Arbitrum	No mempool. Only Sequencer FIFO.	N/A	N/A	N/A
zkSync Era	Sequencer only	N/A	N/A	N/A
Polygon zkEVM	Sequencer only	N/A	N/A	N/A
Optimism	Private to Sequencer	N/A	N/A	N/A
Oasis Saphire	Confidential mempool	N/A	N/A	N/A
NEAR	No mempool	N/A	N/A	N/A
Aurora	No mempool	N/A	N/A	N/A
Solana	No mempool	N/A	N/A	N/A
Scroll	Publicly available through Sequencer.	N/A	N/A	N/A
Ronin	Available to everyone	Not available on Chainstack	N/A	N/A
Aptos	Available to everyone but there is no transaction stream	Full or archive node deployment	N/A	N/A
Gnosis Chain	Available to everyone	On a dedicated node.	Any configuration	Gnosis txpool_content
Cronos	No mempool. Only Sequencer FIFO.	N/A	N/A	N/A
Filecoin	Available to everyone	Full node deployment	20,000 pending messages	Filecoin MpoolPending
Fantom	Available to everyone	On a dedicated node.	4096 pending transactions	Fantom txpool_content
Starknet	Private to Sequencer	N/A	N/A	N/A
Tezos	Available to everyone	Full or archive node deployment	240 blocks	Tezos pending_operations
Bitcoin	Available to everyone	Full node deployment	mempool size: 300 MB mempool tx expiry: 336 hours (14 days)	Bitcoin getrawmempool

Ethereum txpool_content

curl -X POST \
     -H "Content-Type: application/json" \
     --data '{"jsonrpc":"2.0","method":"txpool_content","params":[],"id":1}' \
     YOUR_CHAINSTACK_NODE

Polygon txpool_content

curl -X POST \
     -H "Content-Type: application/json" \
     --data '{"jsonrpc":"2.0","method":"txpool_content","params":[],"id":1}' \
     YOUR_CHAINSTACK_NODE

BSC txpool_content

curl -X POST \
     -H "Content-Type: application/json" \
     --data '{"jsonrpc":"2.0","method":"txpool_content","params":[],"id":1}' \
     YOUR_CHAINSTACK_NODE

Gnosis txpool_content

curl -X POST \
     -H "Content-Type: application/json" \
     --data '{"jsonrpc":"2.0","method":"txpool_content","params":[],"id":1}' \
     YOUR_CHAINSTACK_NODE

Filecoin MpoolPending

curl -X POST \
     -H "Content-Type: application/json" \
     --data '{ "jsonrpc": "2.0", "method": "Filecoin.MpoolPending", "params": [null], "id": 1 }' \
     YOUR_CHAINSTACK_NODE

Fantom txpool_content

curl -X POST \
     -H "Content-Type: application/json" \
     --data '{"jsonrpc":"2.0","method":"txpool_content","params":[],"id":1}' \
     YOUR_CHAINSTACK_NODE

Tezos pending_operations

curl -X GET "YOUR_CHAINSTACK_NODE/chains/main/mempool/pending_operations"

Bitcoin getrawmempool

curl -X POST \
     -H "Content-Type: application/json" \
     --data '{"jsonrpc": "2.0", "id":"curltest", "method": "getrawmempool", "params": [] }' \
     YOUR_CHAINSTACK_NODE