AsyncAPI channel · Optimism · Optimism (OP Stack) WebSocket JSON-RPC API

eth_subscribe.newHeads

Subscription that pushes a notification each time a new block header is added to the chain. Standard op-geth (upstream go-ethereum) behaviour; the OP Stack does not add custom fields to the header itself, though consumers should expect L2-specific block production cadence (~2s on OP Mainnet, faster with Flashblocks preconfirmations).

Open source AsyncAPI → All Optimism channels Optimism provider profile
Provider: Optimism AsyncAPI: v2.6.0 Spec: Optimism (OP Stack) WebSocket JSON-RPC API Operations: 2 Messages: 3

Channel address

eth_subscribe.newHeads

Operations

publish
subscribeNewHeads
Subscribe to new block headers (`eth_subscribe("newHeads")`).
onNewHead
Receive a notification for each new block header.

Messages

SubscribeNewHeadsRequest
JSON-RPC request to subscribe to new block headers.
Content-Type: application/json
SubscribeResponse
JSON-RPC response containing the subscription id.
Content-Type: application/json
NewHeadNotification
Notification carrying a new block header.
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.

Browse every event-driven channel on the APIs.io network or compare with the broader Agent Skill and MCP server surfaces of the same providers.

Work with this as data

Every channel here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for event channels

4 MCP tools reach this
  • find_channelsBrowse and filter every channel in the catalog.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
This channel 
curl "https://apis.io/api/v1/channels/eth-subscribe-newheads"
All event channels 
curl "https://apis.io/api/v1/channels?limit=25"

Calls without X-API-Key need no key. Calls with it need a paid plan — get a key.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.