POST
/
evm
ots_getHeaderByNumber
curl --request POST \
  --url https://hyperliquid-mainnet.core.chainstack.com/4f8d8f4040bdacd1577bff8058438274/evm \
  --header 'Content-Type: application/json' \
  --data '{
  "jsonrpc": "2.0",
  "method": "ots_getHeaderByNumber",
  "params": [
    1000
  ],
  "id": 1
}'
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "number": "0x3e8",
    "hash": "0xe8399bf41516f5ca663c79bc30db02b4989385c2f3a96f42958dea5753cbf4a9",
    "parentHash": "0x7c8f6a0e4d3b2a1c9e5f8b7d4a6c3e9f2b8d5a7c1e4f9b3a6d8c2e5f7a9b4c6d",
    "timestamp": "0x6734e8d0"
  }
}
The ots_getHeaderByNumber JSON-RPC method retrieves block header information by block number on the Hyperliquid EVM blockchain. This Otterscan-specific method provides a lightweight way to fetch block headers without retrieving full block data, making it efficient for block explorer operations.
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​
Parameters

  1. block number (integer, required): The block number to retrieve the header for

​
Response

The method returns a block header object with the following fields:

​
Response structure

  • number — the block number
  • hash — the block hash
  • parentHash — the parent block hash
  • nonce — proof-of-work nonce (always 0x0000000000000000 for PoS)
  • sha3Uncles — SHA3 hash of the uncles data
  • logsBloom — bloom filter for the logs
  • transactionsRoot — root of the transaction trie
  • stateRoot — root of the final state trie
  • receiptsRoot — root of the receipts trie
  • miner — address of the beneficiary
  • difficulty — difficulty for this block
  • totalDifficulty — total difficulty of the chain until this block
  • extraData — extra data field of this block
  • size — size of this block in bytes
  • gasLimit — maximum gas allowed in this block
  • gasUsed — total gas used by all transactions
  • timestamp — Unix timestamp of the block
  • mixHash — mix hash for the block
  • baseFeePerGas — base fee per gas (post-EIP-1559)

​
Usage example

Shell
curl -X POST https://hyperliquid-mainnet.core.chainstack.com/4f8d8f4040bdacd1577bff8058438274/evm \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "ots_getHeaderByNumber",
    "params": [1000],
    "id": 1
  }'

​
Example response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "number": "0x3e8",
    "hash": "0xe8399bf41516f5ca663c79bc30db02b4989385c2f3a96f42958dea5753cbf4a9",
    "parentHash": "0x7c8f6a0e4d3b2a1c9e5f8b7d4a6c3e9f2b8d5a7c1e4f9b3a6d8c2e5f7a9b4c6d",
    "nonce": "0x0000000000000000",
    "sha3Uncles": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
    "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
    "transactionsRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
    "stateRoot": "0x9f3c6b0d8e5a2d1f7c9e4b3a8d6c5e2f9a7b4c8d1e6f3a5b7d9c2e4f6a8b3c5d",
    "receiptsRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
    "miner": "0x0000000000000000000000000000000000000000",
    "difficulty": "0x0",
    "totalDifficulty": "0x0",
    "extraData": "0x",
    "size": "0x220",
    "gasLimit": "0x1c9c380",
    "gasUsed": "0x0",
    "timestamp": "0x6734e8d0",
    "mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "baseFeePerGas": "0x7"
  }
}

​
Use cases

The ots_getHeaderByNumber method is essential for:
  • Block explorers: Efficiently fetch block header information without full block data
  • Light clients: Verify blockchain state with minimal data requirements
  • Node detection: Identify if a node supports Otterscan APIs
  • Block monitoring: Track new blocks with reduced bandwidth usage
  • Chain analysis: Analyze block production patterns and timing
  • Header verification: Validate block headers for security checks
  • Timestamp tracking: Monitor block timestamps for time-based operations
  • Gas analysis: Track gas usage and limits across blocks
  • Fork detection: Monitor chain reorganizations via parent hash tracking
  • Performance optimization: Reduce data transfer when only header data is needed
This method is part of the Otterscan API suite, providing optimized access patterns for blockchain exploration tools.

Body

application/json
​
jsonrpc
enum<string>
default:2.0
required

JSON-RPC version

Available options:
2.0
​
method
enum<string>
default:ots_getHeaderByNumber
required

The RPC method name

Available options:
ots_getHeaderByNumber
​
params
any[]
required

Parameters: [block number]

​
id
integer
default:1
required

Request identifier

Response

200 - application/json

Successful response with block header data

​
jsonrpc
string

JSON-RPC version

​
id
integer

Request identifier

​
result
object

Block header object