Polkadot JSON-RPC API (Relaychain)

JSON-RPC API reference for the Polkadot Relaychain. Explore method list, request examples, and how to connect to GetBlock's Polkadot RPC endpoints

The Polkadot JSON-RPC API exposes the relay chain's Substrate node interface over JSON-RPC 2.0. Methods are grouped into namespaces (chain_, state_, system_, payment_, grandpa_, and others). Requests POST a JSON-RPC 2.0 body to the endpoint; the method is selected by the body.

This reference documents the stable HTTP methods. GetBlock's node also exposes WebSocket subscription methods (chain_subscribe*, state_subscribe*, grandpa_subscribe*), the newer JSON-RPC spec (chainHead_v1_*, chainSpec_v1_*, transaction_v1_*), and node-administration methods; those are reached over WebSocket or restricted on shared endpoints.

Base URL

HTTPS

https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/

WebSocket

wss://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/

The Polkadot.js API (@polkadot/api) connects over the WebSocket endpoint. Each method page below includes a Polkadot.js example.

Available Methods

Account

Method	Description
account_nextIndex	Returns the next nonce for an account, including any transactions already queued in the pool
system_accountNextIndex	Returns the next nonce for an account, including transactions already in the pool

Author

Method	Description
author_pendingExtrinsics	Returns the extrinsics currently in the node's transaction pool that are waiting to be included in a block
author_submitExtrinsic	Submits a signed extrinsic to the node's transaction pool for inclusion in a block and returns its hash

Chain

Method	Description
chain_getBlock	Returns a full block by its hash, including the header and the scale-encoded extrinsics it contains
chain_getBlockHash	Returns the block hash for a given block number
chain_getFinalizedHead	Returns the hash of the most recently finalized block
chain_getHeader	Returns the header of a block by its hash, without the extrinsics
chain_getRuntimeVersion	Returns the runtime version at a given block

State

Method	Description
state_getRuntimeVersion	Returns the runtime version at a given block, including the spec name, spec version, and the supported runtime api versions
state_getMetadata	Returns the scale-encoded runtime metadata at a given block
state_getStorage	Returns the raw scale-encoded value stored at a storage key, at a given block
state_getStorageHash	Returns the hash of the value stored at a storage key, at a given block
state_getStorageSize	Returns the size in bytes of the value stored at a storage key, at a given block
state_getKeys	Returns the storage keys that start with a given prefix, at a given block
state_getKeysPaged	Returns a page of storage keys starting from a prefix, bounded by a count and an optional start key
state_getPairs	Returns the key/value pairs under a storage prefix, at a given block
state_queryStorageAt	Returns the current values for a list of storage keys at a given block, in a single call
state_call	Executes a runtime api call by name with scale-encoded arguments and returns the scale-encoded result, at a given block
state_getReadProof	Returns a merkle read proof for a set of storage keys at a given block
state_getChildReadProof	Returns a merkle read proof for keys in a child trie at a given block
state_traceBlock	Re-executes a block and returns storage access and event traces filtered by the given targets, storage keys, and methods

System

Method	Description
system_chain	Returns the human-readable name of the chain the node is connected to
system_chainType	Returns the type of the chain the node is connected to, such as live, local, or development
system_health	Returns the health of the node, including its peer count, whether it is syncing, and whether it is expected to have peers
system_properties	Returns chain-specific properties, including the token symbol, token decimals, and ss58 address format
system_version	Returns the version string of the node's client software
system_name	Returns the name of the node's client implementation
system_nodeRoles	Returns the roles the node performs on the network, such as full or authority
system_syncState	Returns the sync state of the node: the block it started syncing from, the current block, and the highest known block
system_peers	Returns details of the peers currently connected to the node
system_localPeerId	Returns the base-58 encoded libp2p peer id of the local node
system_localListenAddresses	Returns the libp2p multiaddresses the local node is listening on
system_reservedPeers	Returns the set of reserved peers configured on the node
system_dryRun	Dry-runs an extrinsic against the current state and returns the encoded result without submitting it

Payment

Method	Description
payment_queryInfo	Returns the weight and estimated fee for a submitted extrinsic
payment_queryFeeDetails	Returns the breakdown of the inclusion fee for an extrinsic: the base fee, length fee, and adjusted weight fee

Consensus (GRANDPA & BEEFY)

Method	Description
grandpa_roundState	Returns the state of the current grandpa voting round, including prevotes and precommits and their weights
grandpa_proveFinality	Returns a grandpa finality proof for a given block number, if available
beefy_getFinalizedHead	Returns the hash of the latest block finalized by beefy

Child State

Method	Description
childstate_getKeys	Returns the keys in a child trie that match a prefix, at a given block
childstate_getKeysPaged	Returns a page of keys in a child trie starting from a prefix, bounded by a count and an optional start key
childstate_getStorage	Returns the value stored at a key within a child trie, at a given block
childstate_getStorageHash	Returns the hash of the value stored at a key within a child trie, at a given block
childstate_getStorageSize	Returns the size in bytes of the value stored at a key within a child trie, at a given block

MMR

Method	Description
mmr_root	Returns the merkle mountain range (mmr) root at a given block
mmr_generateProof	Generates an mmr proof for one or more block numbers, returning the leaves and the proof needed to verify them against the mmr root
mmr_verifyProof	Verifies an mmr proof for a set of leaves against the node's mmr state and returns whether the proof is valid

RPC

Method	Description
rpc_methods	Returns the list of json-rpc methods the node exposes

Support

• Support: [e-mail]

See Also

• Polkadot.js API

• Polkadot (DOT)