> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chainstack.com/llms.txt
> Use this file to discover all available pages before exploring further.

# getShardBlockProof | TON v2

> The getShardBlockProof method retrieves the proof of a specific shard block in the TON blockchain. Use it on TON v2 via Chainstack.

The `getShardBlockProof` method retrieves the proof of a specific shard block in the TON blockchain. This method is crucial for verifying the authenticity and inclusion of shard blocks within the overall TON blockchain structure.

<Note>
  **TON billing: full or archive by block age**

  This method is billed as archive (2 RUs) when the requested block is 128 or more seqno behind the tip, and full (1 RU) otherwise. See [Request units — TON method scope](/docs/request-units#ton-method-scope).
</Note>

## JSON-RPC examples

```shell Shell theme={"system"}
curl -X POST \
  'https://ton-mainnet.core.chainstack.com/f2a2411bce1e54a2658f2710cd7969c3/api/v2/jsonRPC' \
  -H 'Content-Type: application/json' \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "getShardBlockProof",
    "params": {
      "workchain": -1,
      "shard": "-9223372036854775808",
      "seqno": 39064874
    }
  }'
```

## Parameters

* `workchain` (integer, required) — The ID of the workchain. Example: `-1` for the masterchain.
* `shard` (integer, required) — The ID of the shard. Example: `-9223372036854775808` for the masterchain.
* `seqno` (integer, required) — The sequence number of the block. Example: `39064874`.

## Response

* `masterchain_block_root_hash` (string) — The root hash of the masterchain block that includes this shard block.
* `masterchain_block_seq_no` (integer) — The sequence number of the masterchain block.
* `links` (array of objects) — An array of link objects, each containing:
  * `from` (string) — The source block hash.
  * `to` (string) — The destination block hash.
  * `dest_proof` (string) — The proof of the destination block.
  * `proof` (string) — The proof of the link.
* `block_header` (string) — The header of the shard block.

## Use case

A possible use case for the `getShardBlockProof` method in TON is for applications or services that need to verify the authenticity and inclusion of shard blocks within the TON blockchain. This method can be used to:

1. Implement light clients that can verify shard blocks without downloading the entire blockchain.
2. Provide cryptographic proof of a shard block's inclusion in the blockchain.
3. Verify cross-shard transactions by proving the existence of blocks in different shards.
4. Build block explorers that can show detailed proof information for each block.


## OpenAPI

````yaml openapi/ton_node_api/v2/getShardBlockProof.json GET /getShardBlockProof
openapi: 3.0.0
info:
  title: getShardBlockProof example
  version: 1.0.0
  description: >-
    This is an API example for getShardBlockProof, a method to retrieve the
    proof of a specific shard block in the TON blockchain.
servers:
  - url: >-
      https://ton-mainnet.core.chainstack.com/f2a2411bce1e54a2658f2710cd7969c3/api/v2
security: []
paths:
  /getShardBlockProof:
    get:
      tags:
        - TON Operations
      summary: getShardBlockProof
      operationId: getShardBlockProof
      parameters:
        - name: workchain
          in: query
          required: true
          description: The workchain ID
          schema:
            type: integer
            default: -1
          example: -1
        - name: shard
          in: query
          required: true
          description: The shard ID
          schema:
            type: string
            default: '-9223372036854775808'
          example: '-9223372036854775808'
        - name: seqno
          in: query
          required: true
          description: The sequence number of the block
          schema:
            type: integer
            default: 39064874
          example: 39064874
      responses:
        '200':
          description: Proof of the specified shard block
          content:
            application/json:
              schema:
                type: object
                properties:
                  masterchain_block_root_hash:
                    type: string
                    description: The root hash of the masterchain block
                  masterchain_block_seq_no:
                    type: integer
                    description: The sequence number of the masterchain block
                  links:
                    type: array
                    items:
                      type: object
                      properties:
                        from:
                          type: string
                          description: The source block hash
                        to:
                          type: string
                          description: The destination block hash
                        dest_proof:
                          type: string
                          description: The proof of the destination block
                        proof:
                          type: string
                          description: The proof of the link
                  block_header:
                    type: string
                    description: The header of the shard block

````