> ## Documentation Index > Fetch the complete documentation index at: https://ton.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Get Block Header > Get metadata of a given block. ## OpenAPI ````yaml get /getBlockHeader openapi: 3.1.0 info: title: TON HTTP API description: > This API enables HTTP access to TON blockchain - getting accounts and wallets information, looking up blocks and transactions, sending messages to the blockchain, calling get methods of smart contracts, and more. In addition to REST API, all methods are available through [JSON-RPC endpoint](#json%20rpc) with `method` equal to method name and `params` passed as a dictionary. The response contains a JSON object, which always has a boolean field `ok` and either `error` or `result`. If `ok` equals true, the request was successful and the result of the query can be found in the `result` field. In case of an unsuccessful request, `ok` equals false and the error is explained in the `error`. API Key should be sent either as `api_key` query parameter or `X-API-Key` header. version: 2.0.0 servers: - url: https://toncenter.com/api/v2 - url: https://testnet.toncenter.com/api/v2 security: [] tags: - name: accounts description: Information about accounts. - name: blocks description: Information about blocks. - name: transactions description: Fetching and locating transactions. - name: get config description: Get blockchain config - name: run method description: Run get method of smart contract. - name: send description: Send data to blockchain. - name: json rpc description: JSON-RPC endpoint. paths: /getBlockHeader: get: tags: - blocks summary: Get Block Header description: Get metadata of a given block. operationId: get_block_header_getBlockHeader_get parameters: - required: true schema: type: integer title: Workchain name: workchain in: query - required: true schema: type: integer title: Shard name: shard in: query - required: true schema: type: integer title: Seqno name: seqno in: query - required: false schema: type: string title: Root Hash name: root_hash in: query - required: false schema: type: string title: File Hash name: file_hash in: query responses: '200': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/GetBlockHeaderResponse' examples: sample: summary: Block header example value: ok: true result: '@type': blocks.header id: '@type': ton.blockIdExt workchain: -1 shard: '-9223372036854775808' seqno: 1 root_hash: 8GYhhrigd8CwZGrRT59iulLDcgiTYuvOAzFJxugc0Ts= file_hash: V+XzykEwun4yePZhAEPZk77RbMfMOgS/S4GiJkSKY6s= global_id: -239 version: 0 after_merge: false after_split: false before_split: false want_merge: false want_split: false validator_list_hash_short: -1447544682 catchain_seqno: 0 min_ref_mc_seqno: 1 is_key_block: false prev_key_block_seqno: 0 start_lt: '1000000' end_lt: '1000012' gen_utime: 1573822385 prev_blocks: - '@type': ton.blockIdExt workchain: -1 shard: '-9223372036854775808' seqno: 0 root_hash: F6OpKZKqvqeFp6CQmFomXNMfMj2EnaUSOXN+Mh+wVWk= file_hash: XplPz01CXAps5qeSWUtxcyBfdAo5zVb1N979KLSKD24= '@extra': 1755814930.1088252:0:0.1467032130574265 '422': description: Validation Error '504': description: Lite Server Timeout security: [] components: schemas: GetBlockHeaderResponse: allOf: - $ref: '#/components/schemas/TonResponse' - type: object properties: result: $ref: '#/components/schemas/BlocksHeader' description: Header information of the specified block. TonResponse: properties: ok: type: boolean title: Ok result: anyOf: - type: string - items: {} type: array - type: object title: Result error: type: string title: Error code: type: integer title: Code type: object required: - ok title: TonResponse BlocksHeader: type: object description: Block header information. properties: '@type': type: string example: blocks.header id: $ref: '#/components/schemas/TonBlockIdExt' description: Extended identifier of the block. global_id: type: integer description: Global network identifier. version: type: integer description: Block format version. after_merge: type: boolean description: True if block was created after a merge. after_split: type: boolean description: True if block was created after a split. before_split: type: boolean description: True if block was created before a split. want_merge: type: boolean description: Indicates if validators wanted a merge. want_split: type: boolean description: Indicates if validators wanted a split. validator_list_hash_short: type: integer description: Short hash of validator list. catchain_seqno: type: integer description: Catchain sequence number. min_ref_mc_seqno: type: integer description: Minimum referenced masterchain seqno. is_key_block: type: boolean description: True if this block is a key block. prev_key_block_seqno: type: integer description: Previous key block sequence number. start_lt: type: string description: Starting logical time. end_lt: type: string description: Ending logical time. gen_utime: type: integer description: Block generation UNIX timestamp. prev_blocks: type: array description: List of previous block identifiers. items: $ref: '#/components/schemas/TonBlockIdExt' '@extra': type: string description: Extra metadata for the response. required: - id - global_id - version - gen_utime TonBlockIdExt: type: object properties: '@type': type: string example: ton.blockIdExt workchain: type: integer shard: type: string description: 64-bit signed integer as string seqno: type: integer root_hash: type: string file_hash: type: string required: - workchain - shard - seqno - root_hash - file_hash description: Extended block identifier. ````