txpool

The txpool namespace provides methods for inspecting and managing the transaction pool (mempool) in Erigon. These methods allow you to view pending and queued transactions, providing insight into the current state of unconfirmed transactions. In Erigon, the txpool namespace is implemented through the TxPoolAPI interface and TxPoolAPIImpl struct.

The TxPool namespace must be explicitly enabled using the --http.api flag when starting the RPC Daemon. These methods are particularly useful for monitoring transaction pool status and debugging transaction submission issues.

Transaction Pool Architecture

• Erigon's transaction pool is organized into three sub-pools: pending (executable), baseFee (insufficient base fee), and queued (nonce gaps)
• The txpool_content, txpool_contentFrom and txpool_status methods expose only the pending and queued categories, as defined by the ethereum/execution-apis specification. Transactions in the internal baseFee sub-pool are nonce-ready and otherwise valid, but are not executable at the current base fee: they wait for the fee condition to change. They are reported as pending, matching Geth
• Blob transactions (type 3) are not reported by txpool_content and txpool_contentFrom, matching Geth and Nethermind. They are still counted by txpool_status
• The pool can run either integrated within the main Erigon process or as a separate service for scalability
• Transaction pool methods communicate via gRPC with the TxPool service when running in external mode

Implementation Details

• The TxPoolAPIImpl uses a proto_txpool.TxpoolClient to communicate with the transaction pool service
• All transactions are decoded from RLP format and converted to ethapi.RPCTransaction objects for JSON-RPC responses
• The implementation handles transaction categorization based on the TxnType field from the pool service

External vs Internal Mode

• Internal Mode: Transaction pool runs within the main Erigon process (default configuration)
• External Mode: Transaction pool runs as a separate service, requiring explicit configuration with --txpool.api.addr. External mode requires an external Sentry service and provides better resource isolation

Usage in Development and Testing

• These methods are commonly used for monitoring transaction submission and pool state
• The txpool_status method provides quick insight into pool health and congestion
• Transaction pool content methods help debug why transactions may not be getting mined

Configuration and Limits

• Transaction pool limits can be configured via flags like --txpool.globalslots, --txpool.globalbasefeeslots, and --txpool.globalqueue
• The pool supports various transaction types including blob transactions with separate limits
• Pool configuration is managed through the txpoolcfg.Config structure

Availability

• The txpool namespace is available when included in the --http.api flag
• Methods are marked as "remote" in the documentation, indicating they communicate with external services
• All txpool methods are available on both HTTP and WebSocket connections

---

txpool_content

Returns the content of the transaction pool, organized by sender address and categorized into pending and queued transactions. Blob transactions are not returned.

Parameters

None

Example

curl -s --data '{"jsonrpc":"2.0","method":"txpool_content","params":[],"id":"1"}' -H "Content-Type: application/json" -X POST http://localhost:8545

Returns

Type	Description
Object	Transaction pool content organized by sub-pool type
pending	Object
queued	Object

---

txpool_contentFrom

Returns the content of the transaction pool for a specific sender address, categorized into pending and queued transactions. The same rules as txpool_content apply.

Parameters

Parameter	Type	Description
address	DATA, 20 BYTES	The sender address to query transactions for

Example

curl -s --data '{"jsonrpc":"2.0","method":"txpool_contentFrom","params":["0xb60e8dd61c5d32be8058bb8eb970870f07233155"],"id":"1"}' -H "Content-Type: application/json" -X POST http://localhost:8545

Returns

Type	Description
Object	Transaction pool content for the specified address
pending	Object
queued	Object

---

txpool_status

Returns the current status of the transaction pool, with the count of pending and queued transactions.

Parameters

None

Example

curl -s --data '{"jsonrpc":"2.0","method":"txpool_status","params":[],"id":"1"}' -H "Content-Type: application/json" -X POST http://localhost:8545

Returns

Type	Description
Object	Transaction pool status counts
pending	QUANTITY
queued	QUANTITY