# chain

###

### **getBlock(hash?: `BlockHash`): `SignedBlock`**

* **interface**: `api.rpc.chain.getBlock`
* **jsonrpc**: `chain_getBlock`
* **summary**: Gets the header and body of the target chain block

### **getBlockHash(blockNumber?: `BlockNumber`): `BlockHash`**

* **interface**: `api.rpc.chain.getBlockHash`
* **jsonrpc**: `chain_getBlockHash` (alias=`chain_getHead`)
* **summary**: Gets the block hash for a specific block

### **getFinalizedHead(): `BlockHash`**

* **interface**: `api.rpc.chain.getFinalizedHead`
* **jsonrpc**: `chain_getFinalizedHead` (alias=`chain_getFinalisedHead`)
* **summary**: Gets hash of the last finalized block in the canon chain

### **getHeader(hash?: `BlockHash`): `Header`**

* **interface**: `api.rpc.chain.getHeader`
* **jsonrpc**: `chain_getHeader`
* **summary**: Retrieves the header for a specific block

### **subscribeAllHeads(): `Header`**

* **interface**: `api.rpc.chain.subscribeAllHeads`
* **jsonrpc**: `chain_subscribeAllHeads`
* **summary**: Retrieves the newest header via subscription

### **subscribeFinalizedHeads(): `Header`**

* **interface**: `api.rpc.chain.subscribeFinalizedHeads`
* **jsonrpc**: `chain_subscribeFinalizedHeads` (alias=`chain_subscribeFinalisedHeads`)
* **summary**: Retrieves the best finalized header via subscription.

### **subscribeNewHeads(): `Header`**

* **interface**: `api.rpc.chain.subscribeNewHeads`
* **jsonrpc**: `chain_subscribeNewHeads` (alias=`chain_subscribeNewHead`)
* **summary**: Retrieves the best header via subscription.