AsyncAPI channel · Chainstack · Chainstack RPC WebSocket APIs

base/eth_subscribe/newFlashblocks

Subscribe to Chainstack Base Flashblocks preconfirmations. Streams a block snapshot approximately every 200 ms while a block is forming. The snapshot's `hash` and `stateRoot` are zero until the block is finalized.

Open source AsyncAPI → All Chainstack channels Chainstack provider profile
Provider: Chainstack AsyncAPI: v2.6.0 Spec: Chainstack RPC WebSocket APIs Operations: 2 Messages: 2

Channel address

base/eth_subscribe/newFlashblocks

Operations

publish
baseSubscribeNewFlashblocks
Subscribe to newFlashblocks on Base
baseNewFlashblocksNotification
Receive Base newFlashblocks notifications

Messages

baseSubscribeNewFlashblocks
Subscribe to Chainstack Base Flashblocks preconfirmation snapshots (~200 ms cadence).
Content-Type: application/json
ethSubscriptionFlashblock
Push notification carrying a Base Flashblocks block-in-progress snapshot.
Content-Type: application/json

About AsyncAPI

The AsyncAPI specification describes event-driven APIs the way OpenAPI describes request/response APIs. A channel is the named pipe — a webhook URL, a Kafka topic, a WebSocket route, an MQTT subject — that producers and consumers publish or subscribe to. Each channel carries one or more messages with structured payloads, and an operation declares whether a given party sends or receives on that channel.

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