newFlashblockTransactions

Subscribe to receive each transaction as it is pre-confirmed into a Flashblock. Only available on Flashblocks WebSocket endpoints.

Subscribe via eth_subscribe to receive each transaction as it is pre-confirmed into a Flashblock. Pass true as the second parameter to receive full transaction and log data.

Only available on Flashblocks WebSocket endpoints: wss://mainnet-preconf.base.org / wss://sepolia-preconf.base.org.

Requires base/base minimum client version v0.3.1.

Each subscription emits one item per WebSocket message. Events arrive approximately every 200ms. If your handler performs heavy processing per event, throttle or debounce it to avoid blocking.

Parameters

subscriptionType · string · required

Must be "newFlashblockTransactions".

full · boolean

If true, each notification includes the full transaction object and associated logs. Defaults to false (minimal data only).

Returns

result · string

Hex-encoded subscription ID.

Example

Subscribe

{"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["newFlashblockTransactions"]}