AsyncAPI channel · Kusama · Kusama JSON-RPC Subscription API

chain_subscribeFinalizedHeads

Emits a header only once a block is finalized by GRANDPA. This is the subscription that matters for anything financial — a block on the best chain can still be reorged away; a finalized block cannot. Unsubscribe with chain_unsubscribeFinalizedHeads. The British spelling chain_subscribeFinalisedHeads is also served as an alias.

Open source AsyncAPI → All Kusama channels Kusama provider profile
Provider: Kusama AsyncAPI: v3.0.0 Spec: Kusama JSON-RPC Subscription API Operations: 1 Messages: 1

Channel address

chain_subscribeFinalizedHeads

Operations

receive
receiveFinalizedHeads
Receive block headers only after GRANDPA finalization.

Messages

blockHeader
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/chain-subscribefinalizedheads"
All event channels 
curl "https://apis.io/api/v1/channels?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

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.