> ## Documentation Index > Fetch the complete documentation index at: https://docs.qu.ai/llms.txt > Use this file to discover all available pages before exploring further. # getHeaderByHash > Returns the header for a given block hash. ## OpenAPI ````yaml openapi-getHeaderByHash POST / openapi: 3.0.0 info: title: Quai JSON RPC API version: 1.0.0 servers: - url: https://rpc.quai.network/cyprus1 security: [] paths: /: post: summary: quai_getHeaderByHash description: Returns the block header for a given block hash. requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/Request' responses: '200': description: Successful response content: application/json: schema: $ref: '#/components/schemas/Response' components: schemas: Request: type: object required: - jsonrpc - method - params - id properties: jsonrpc: type: string example: '2.0' enum: - '2.0' method: type: string description: The name of the method to be invoked. example: quai_getHeaderByHash enum: - quai_getHeaderByHash params: type: array description: The block hash for which the header should be retrieved. items: type: string maxItems: 1 minItems: 1 example: - '0xaf6c0730ada766a1f2a922ae2c6653c637f4a95b921c6cba3c919776222656cf' id: type: integer description: A unique identifier for the request. example: 1 Response: type: object properties: jsonrpc: type: string example: '2.0' result: type: object properties: baseFeePerGas: type: string description: The base fee per gas for the block. efficiencyScore: type: string description: >- The ratio of entropy reduced by the block to the entropy reduced by the uncles in this block. An estimate of how much work was wasted by the block. etxEligibleSlices: type: string description: >- A 256 bit hex encoded indicator of which other zones are eligible to recieve external transactions in this block. The value of each bit is 1 if the corresponding zone is eligible, 0 if not. etxRollupRoot: type: string description: >- Hash of all external transactions emitted since the previous coincident block. etxSetRoot: type: string description: The hash of all of the external transactions in the state trie. evmRoot: type: string description: The root hash of the EVM Ledger state trie. exchangeRate: type: string description: The exchange rate of Quai and Qi for this block. expansionNumber: type: string description: >- The number of dynamic shard expansions that have occurred since genesis. extraData: type: string description: Arbitrary hex-encoded extra data included in this block. gasLimit: type: string description: The maximum gas allowed in this block. gasUsed: type: string description: The total used gas by all transactions in this block. interlinkRootHash: type: string description: >- Hash of the block hashes of the most recent interlink blocks at each level of the hierarchy. manifestHash: type: array description: >- Hash of all of the blocks confirmed in subordinate chains to this block since the last coincident block. items: type: string number: type: array description: Integer block numbers at each level of the hierarchy. items: type: string outboundEtxsRoot: type: string description: >- Hash of all outbound external transactions emitted in this block. parentDeltaEntropy: type: array description: >- The change in entropy since the previous coincident block in each level of the hierarchy. items: type: string parentEntropy: type: array description: >- Total entropy reduced since genesis prior to this block in each level of the hierarchy. items: type: string parentHash: type: array description: The hash of the parent block for each level of the hierarchy. items: type: string parentUncledDeltaEntropy: type: array description: >- The entropy reduction of uncles since the previous coincident block in all subordinate chains to this block for each level of the hierarchy. items: type: string primeTerminusHash: type: string description: >- The hash of the most recent prime block the shard this block was included in. quaiStateSize: type: string description: The size of the Quai Ledger state at this block. receiptsRoot: type: string description: Receipt trie root hash of the block. secondaryCoinbase: type: string description: >- The secondary coinbase address of the miner of this block. Only transaction fees are paid to this address. size: type: string description: The size of the block header in bytes. stateLimit: type: string description: The total number of bytes of state allowed in this block. stateUsed: type: string description: The number of bytes used in the state trie within this block. thresholdCount: type: string description: >- The number of prime blocks since the uncle rate has crossed the rate threshold for dynamic expansion. Specification denoted by Quai Improvement Proposal 8. transactionsRoot: type: string description: The root of the transaction trie of the block. uncleHash: type: string description: The hash of the uncles data in the block. uncledEntropy: type: string description: The entropy reduced by all uncles included in this block. utxoRoot: type: string description: The root hash of the UTXO ledger state trie. woHeader: type: object description: The work object header. properties: coinbase: type: string description: The address of the account that mined this block. difficulty: type: string description: The difficulty achieved by this block. headerHash: type: string description: The hash of the work object header data. location: type: string description: The 4 byte zone location identifier of the block. lock: type: string description: >- The duration that the block rewards for this block are locked. mixHash: type: string description: The ProgPOW mix hash of this block. nonce: type: string description: The random number used in the valid proof-of-work. number: type: string description: The block number. parentHash: type: string description: The hash of the parent block this block was mined on. primaryCoinbase: type: string description: >- The primary coinbase of the miner of this block. Determines whether block rewards are paid out in Quai or Qi. primeTerminusNumber: type: string description: >- The number of the most recent prime block the shard that this block was included in. timestamp: type: string description: Timestamp for when this block was collated. txHash: type: string description: >- The hash of one or more transactions worked and included in the block. example: baseFeePerGas: '0xa410' efficiencyScore: '0x1' etxEligibleSlices: '0x0100000000000000000000000000000000000000000000000000000000000000' etxRollupRoot: '0xb388088d2258438dff45de21427abe830b13b8c1e533f5a0e9a81a8d8e9913fc' etxSetRoot: '0x223f55cafa1ba1b9b6bce93fd47914e79e3dcd73d580401c20e9a2a4966c1ee4' evmRoot: '0xa2a4c58c572807cd5f65d744aa64425dbcc68f0186849434e69ffdccd6b9607b' exchangeRate: '0x38d7ea4c68000' expansionNumber: '0x0' extraData: '0xd78776302e31392e3088676f312e32332e31856c696e7578' gasLimit: '0x2625a00' gasUsed: '0x2425e0' interlinkRootHash: '0xd6c4c98f71601591ab7d2de87becd40bc6cc2a7e8121a8736b1a6ca1b02f90d8' manifestHash: - >- 0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421 - >- 0x847c7ece49c07a0930955a99393eef02926f3b4504986f69e2a928e3218abbaf - >- 0x980e84749d3d805de6fcbaeb54502f21b34dcd9adc12caa8c762130cf1d5601c number: - '0x3' - '0x6' outboundEtxsRoot: '0x79709f3dc4fb0abb448b5510282ff03300bdc21f2643458f2be5278a8b14a6fb' parentDeltaEntropy: - '0x0' - '0x0' - '0x6cd932130602527ba6' parentEntropy: - '0x1bdf8a21057ebc05add' - '0x1bdf8a21057ebc05add' - '0x22b5c1a91498aa748b4' parentHash: - >- 0xa85fd2206e4e6cefa52e4cdcc9703966b5ba2adbb653b7a03f35bbdb8bf15164 - >- 0xa85fd2206e4e6cefa52e4cdcc9703966b5ba2adbb653b7a03f35bbdb8bf15164 parentUncledDeltaEntropy: - '0x0' - '0x0' - '0x0' primeTerminusHash: '0xa85fd2206e4e6cefa52e4cdcc9703966b5ba2adbb653b7a03f35bbdb8bf15164' quaiStateSize: '0xad2d' receiptsRoot: '0x28f04315a3c72cd71aad9c19d872fa1ce9da69c2f0b923777fbd7d4083bb8ad4' secondaryCoinbase: '0x00A3E45AA16163F2663015B6695894D918866d19' size: '0x2a8' stateLimit: '0x2625a00' stateUsed: '0x0' thresholdCount: '0x0' transactionsRoot: '0xea3b95e9dca1731c0224bab7c70a2b356f1f339b3d21bc93d42fb5918825e08d' uncleHash: '0xaa7efa095d8a2395ca710cbd792b52705e75e89c97225426317c74503dcc893f' uncledEntropy: '0x0' utxoRoot: '0xabf4854703f6b830a729ee8f667c47e1de8380f79b645b84cd3930c76c13f5d9' woHeader: difficulty: '0x6c4e7edba' headerHash: >- 0xa2d7d51a17c5798441bb91c13db5ac4dc6e699d4b4908f48664a327fc734b216 location: '0x0000' lock: '0x1' mixHash: >- 0x196b6d605784efcb60aae22923db8f52b54e3f12e19d69003028d2969df28247 nonce: '0x8dcd00000035efd3' number: '0x10' parentHash: >- 0x8714e00f8e4775001dca3f2b9cd8c80d0e286d17a6a1f3b2216cdf6ea15e66ed primaryCoinbase: '0x0003e45Aa16163f2663015B6695894D918866D19' primeTerminusNumber: '0x2' timestamp: '0x66fd78bf' txHash: >- 0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421 description: The block header data for the given hash. id: type: integer example: 1 ````