Mempool configurations

Configure mempool access on your Chainstack nodes for pending transaction monitoring, MEV research, and real-time transaction pool data on EVM networks.

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.

On protocols with no public mempool, pending-transaction methods like eth_newPendingTransactionFilter and eth_subscribe("newPendingTransactions") return empty by design — pending transactions are visible only to the sequencer. On Base and Optimism, follow transactions in real time with Flashblocks instead — see the how-to guides (Base, Optimism) or how Flashblocks works (Base, Optimism).

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
Optimism	Private to Sequencer	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
Sonic	Available to everyone	On a dedicated node	4096 pending transactions	txpool_*
Fantom	Available to everyone	On a dedicated node	4096 pending transactions	txpool_*
TRON	Available to everyone	On a dedicated node	4096 pending transactions	txpool_*
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

Shell

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

Polygon txpool_content

Shell

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

BSC txpool_content

Shell

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

Gnosis txpool_content

Shell

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

Filecoin MpoolPending

Shell

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

Shell

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

Tezos pending_operations

Shell

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

Bitcoin getrawmempool

Shell

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

Ake

Director of Developer Experience @ Chainstack
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