> ## Documentation Index > Fetch the complete documentation index at: https://docs.chainstack.com/llms.txt > Use this file to discover all available pages before exploring further. # 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. ## What gives you mempool access Two different things get called mempool access, and they have different requirements. On the EVM chains with a public mempool — Ethereum, Polygon, and BNB Smart Chain: | What you want | Methods | Full mode | Archive mode | | ----------------------------------------- | ---------------------------------------------------------------------------- | ------------- | ------------ | | Watch pending transactions as they arrive | `eth_subscribe("newPendingTransactions")`, `eth_newPendingTransactionFilter` | Available | Available | | Inspect the transaction pool itself | `txpool_content`, `txpool_status`, `txpool_inspect` | Not available | Available | For a live feed of pending transactions, a full-mode node is enough. The feed is the node's view of the public mempool — transactions that reached it over the p2p network, not only the ones you submitted through it. No node sees every pending transaction, as each node's view depends on its peers. The `txpool_*` namespace is the part that needs the archive mode. A [Dedicated Node](/docs/dedicated-node) can serve `txpool_*` in the full mode too — that one is a [customization](/docs/features-availability-across-subscription-plans#node-customization), so ask for it when you deploy. `txpool_*` is also a separate namespace from `debug_*` and `trace_*`, and each one has its own gate: * `txpool_*` — the node mode enables it, not your plan. It works on an archive node even when your plan has no debug and trace access. * `debug_*` and `trace_*` — your [plan](/docs/features-availability-across-subscription-plans#debug-and-trace-apis) enables them. They also work on full-mode nodes, and they do not bring `txpool_*` with them. So enabling the debug and trace APIs on a full-mode node does not give you the pool methods. Calling `txpool_content` on such a node returns: ```json theme={"system"} {"jsonrpc":"2.0","id":1,"error":{"code":-32601,"message":"the method txpool_content is not available"}} ``` Arc is the exception to the split above. It serves the `txpool_*` methods, but its node software blocks pending-transaction visibility outright: `eth_newPendingTransactionFilter` and `eth_subscribe("newPendingTransactions")` return `-32001`, and both `eth_getBlockByNumber("pending")` and `eth_getTransactionBySenderAndNonce` return `null`. See [Arc methods](/docs/arc-methods). To get the `txpool_*` methods, deploy the node in the [archive mode](/docs/protocols-modes-and-types#modes), or ask for them on a full-mode [Dedicated Node](/docs/dedicated-node). Trader Nodes are regional and not every region offers the archive mode, so check [Available clouds, regions, & locations](/docs/nodes-clouds-regions-and-locations) for your region before you deploy. 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](/docs/base-streaming-transactions-flashblocks), [Optimism](/docs/optimism-streaming-transactions-flashblocks)) or how Flashblocks works ([Base](/docs/flashblocks-on-base), [Optimism](/docs/flashblocks-on-optimism)). A subscription that is accepted is not a subscription that delivers. On **World Chain** and **Stable**, `eth_subscribe("newPendingTransactions")` and `eth_newPendingTransactionFilter` both succeed and hand back an ID, then deliver nothing. World Chain is an OP Stack chain, so its pending transactions sit with the sequencer and the `txpool_*` methods are not served at all. On Stable, the `txpool_*` methods do respond, but `txpool_status` reported `pending: 0x0, queued: 0x0` in every one of 30 samples taken over two minutes while 52 transactions confirmed in new blocks over the same window — the pool is not exposed through the EVM JSON-RPC layer. Do not build a pending-transaction feed on either chain. The table structure: * Protocol — protocol name. * Protocol availability — details of the mempool availability on the protocol level. * Chainstack availability — what you need to deploy for the protocol's pool-inspection methods 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](/docs/features-availability-across-subscription-plans#node-customization) it for you on a [Dedicated Node](/docs/dedicated-node) . | Protocol | Protocol availability | Chainstack availability | Client configuration | Example | | --------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------ | ----------------------------------------------------------- | ------------------------------------------------------ | | Ethereum | Available to everyone | [Archive](/docs/protocols-modes-and-types#modes) mode | 4096 pending transactions | [Ethereum txpool\_content](#ethereum-txpool_content) | | Polygon | Available to everyone | [Archive](/docs/protocols-modes-and-types#modes) mode | 4096 pending transactions | [Polygon txpool\_content](#polygon-txpool_content) | | BNB Smart Chain | Available to everyone | [Archive](/docs/protocols-modes-and-types#modes) mode | 4096 pending transactions | [BSC txpool\_content](#bsc-txpool_content) | | Arc | Available, but the node blocks pending-transaction visibility | Available | Not published | [Arc txpool\_content](/reference/arc-txpool-content) | | Base | [Private to Sequencer](https://github.com/base/node/issues/78). | N/A | N/A | N/A | | World Chain | [Private to Sequencer](https://docs.optimism.io/stack/differences#mempool-rules) — OP Stack | N/A — the `txpool_*` methods are not served | N/A | N/A | | Stable | Not exposed through the EVM JSON-RPC — see the note below | The `txpool_*` methods respond, but always empty | N/A | `txpool_*` | | Avalanche | [Available only to validators](https://support.avax.network/en/articles/6158842-nodes-faq). | Not available on Chainstack | N/A | N/A | | TON | External messages are available in mempool | Available | | | | Arbitrum | No mempool. Only [Sequencer FIFO](https://docs.arbitrum.io/learn-more/faq#does-arbitrum-have-a-mempool). | N/A | N/A | N/A | | zkSync Era | Sequencer only | N/A | N/A | N/A | | Optimism | [Private to Sequencer](https://docs.optimism.io/stack/differences#mempool-rules) | N/A | N/A | N/A | | NEAR | [No mempool](https://gov.near.org/t/transaction-fee-discussion/58) | N/A | N/A | N/A | | Aurora | [No mempool](https://gov.near.org/t/transaction-fee-discussion/58) | N/A | N/A | N/A | | Solana | [No mempool](https://docs.solana.com/integrations/retrying-transactions) | N/A | N/A | N/A | | Scroll | [Publicly available through Sequencer](https://docs.scroll.io/en/technology/chain/rollup/). | N/A | N/A | N/A | | Ronin | Available to everyone | Not available on Chainstack | N/A | N/A | | Aptos | [Available to everyone](https://aptos.dev/concepts/validator-nodes#mempool) but there is no [transaction stream](https://github.com/aptos-labs/aptos-core/issues/5200) | [Full or archive node deployment](/docs/protocols-modes-and-types) | N/A | N/A | | Gnosis Chain | Available to everyone | On a [Dedicated Node](/docs/dedicated-node). | Any configuration | [Gnosis txpool\_content](#gnosis-txpool_content) | | Cronos | No mempool. [Only Sequencer FIFO](https://docs.cronos.org/cronos-chain-protocol/cronos-general-faq#if-i-increase-the-gas-price-does-it-help-to-speed-up-my-transaction). | N/A | N/A | N/A | | Filecoin | Available to everyone | [Full node deployment](/docs/protocols-modes-and-types) | 20,000 pending messages | [Filecoin MpoolPending](#filecoin-mpoolpending) | | Sonic | Available to everyone | On a [Dedicated Node](/docs/dedicated-node) | 4096 pending transactions | `txpool_*` | | Fantom | Available to everyone | On a [Dedicated Node](/docs/dedicated-node) | 4096 pending transactions | `txpool_*` | | TRON | Available to everyone | On a [Dedicated Node](/docs/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](/docs/protocols-modes-and-types) | 240 blocks | [Tezos pending\_operations](#tezos-pending_operations) | | Bitcoin | Available to everyone | [Full node deployment](/docs/protocols-modes-and-types) | mempool size: 300 MB mempool tx expiry: 336 hours (14 days) | [Bitcoin getrawmempool](#bitcoin-getrawmempool) | ## Ethereum txpool\_content ```bash Shell theme={"system"} curl -X POST \ -H "Content-Type: application/json" \ --data '{"jsonrpc":"2.0","method":"txpool_content","params":[],"id":1}' \ YOUR_CHAINSTACK_NODE ``` ## Polygon txpool\_content ```bash Shell theme={"system"} curl -X POST \ -H "Content-Type: application/json" \ --data '{"jsonrpc":"2.0","method":"txpool_content","params":[],"id":1}' \ YOUR_CHAINSTACK_NODE ``` ## BSC txpool\_content ```bash Shell theme={"system"} curl -X POST \ -H "Content-Type: application/json" \ --data '{"jsonrpc":"2.0","method":"txpool_content","params":[],"id":1}' \ YOUR_CHAINSTACK_NODE ``` ## Gnosis txpool\_content ```bash Shell theme={"system"} curl -X POST \ -H "Content-Type: application/json" \ --data '{"jsonrpc":"2.0","method":"txpool_content","params":[],"id":1}' \ YOUR_CHAINSTACK_NODE ``` ## Filecoin MpoolPending ```bash Shell theme={"system"} 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 ```bash Shell theme={"system"} curl -X POST \ -H "Content-Type: application/json" \ --data '{"jsonrpc":"2.0","method":"txpool_content","params":[],"id":1}' \ YOUR_CHAINSTACK_NODE ``` ## Tezos pending\_operations ```bash Shell theme={"system"} curl -X GET "YOUR_CHAINSTACK_NODE/chains/main/mempool/pending_operations" ``` ## Bitcoin getrawmempool ```bash Shell theme={"system"} 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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