---
title: "GetBeaconLightClientBootstrapByBlockRoot"
method: GET
path: "/{apiKey}/eth/v1/beacon/light_client/bootstrap/{blockRoot}"
---

# GetBeaconLightClientBootstrapByBlockRoot

`GET /{apiKey}/eth/v1/beacon/light_client/bootstrap/{blockRoot}`

Get `LightClientBootstrap` structure for a requested block root.

Requests the [`LightClientBootstrap`](https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/altair/light-client/sync-protocol.md#lightclientbootstrap) structure corresponding to a given post-Altair beacon block root.
 Depending on the `Accept` header it can be returned either as JSON or SSZ-serialized bytes.

Servers SHOULD provide results as defined in [`create_light_client_bootstrap`](https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/altair/light-client/full-node.md#create_light_client_bootstrap). To fulfill a request, the requested block's post state needs to be known.

## Path parameters

- `apiKey` string, required — <style> .custom-style { color: #048FF4; } </style> For higher throughput, please <span class="custom-style"><a href="../docs/quick-start-guide#-creating-your-api-key-on-the-zan-platform" target="_blank">create your own API key</a></span>.
- `blockRoot` string, hex, required

## Response `200`

Bootstrap structure

- object
  - `version` 'phase0' | 'altair' | 'bellatrix' | 'capella' | 'deneb', required
  - `data` union, required
    - object
      - `header` object, required
        - `beacon` object, required — The [`BeaconBlockHeader`](https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/phase0/beacon-chain.md#beaconblockheader) object from the CL spec.
          - `slot` string, required — The slot to which this block corresponds.
          - `proposer_index` string, required — Index of validator in validator registry.
          - `parent_root` string, hex, required — The signing merkle root of the parent `BeaconBlock`.
          - `state_root` string, hex, required — The tree hash merkle root of the `BeaconState` for the `BeaconBlock`.
          - `body_root` string, hex, required — The tree hash merkle root of the `BeaconBlockBody` for the `BeaconBlock`
      - `current_sync_committee` object, required
        - `pubkeys` string[], required
        - `aggregate_pubkey` string, hex, required — The validator's BLS public key, uniquely identifying them. _48-bytes, hex encoded with 0x prefix, case insensitive._
      - `current_sync_committee_branch` string[], required
    - object
      - `header` object, required
        - `beacon` object, required — The [`BeaconBlockHeader`](https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/phase0/beacon-chain.md#beaconblockheader) object from the CL spec.
          - `slot` string, required — The slot to which this block corresponds.
          - `proposer_index` string, required — Index of validator in validator registry.
          - `parent_root` string, hex, required — The signing merkle root of the parent `BeaconBlock`.
          - `state_root` string, hex, required — The tree hash merkle root of the `BeaconState` for the `BeaconBlock`.
          - `body_root` string, hex, required — The tree hash merkle root of the `BeaconBlockBody` for the `BeaconBlock`
        - `execution` object, required — The [`ExecutionPayload`](https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/capella/beacon-chain.md#executionpayload) object from the CL Capella spec.
          - `parent_hash` string, hex, required
          - `fee_recipient` string, hex, required — An address on the execution (Ethereum 1) network.
          - `state_root` string, hex, required
          - `receipts_root` string, hex, required
          - `logs_bloom` string, hex, required
          - `prev_randao` string, hex, required
          - `block_number` string, required
          - `gas_limit` string, required
          - `gas_used` string, required
          - `timestamp` string, required
          - `extra_data` string, hex, required — Extra data on the execution (Ethereum 1) network.
          - `base_fee_per_gas` string, required
          - `block_hash` string, hex, required
          - `transactions_root` string, hex, required
          - `withdrawals_root` string, hex, required
        - `execution_branch` string[], required
      - `current_sync_committee` object, required
        - `pubkeys` string[], required
        - `aggregate_pubkey` string, hex, required — The validator's BLS public key, uniquely identifying them. _48-bytes, hex encoded with 0x prefix, case insensitive._
      - `current_sync_committee_branch` string[], required

---

[API](https://skmtc.net/zan/apis/zan-getnftmetadata.md) · [All operations](https://skmtc.net/zan/apis/zan-getnftmetadata/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/zan/zan-getnftmetadata/versions/be8fa2338895/schema)