Get a block hash by height.

GET

https://ethw-blockbook.nownodes.io/api/v2/block-index/{height}

Authorizations

ApiKeyAuthApiKeyAuth

api-key string

NOWNodes API key passed in the api-key header.

Returns the block hash for a height on the backend main chain. Blockbook follows the backend main chain; after a rollback or reorg, height lookups resolve to the current main-chain block.

Load estimate: Low; indexed height-to-hash lookup.

live-verified behavior:

Live capture (height 1): the Ethereum genesis-era hash 0x88e96d...06cb6.

Parameters

heightinteger>= 0requiredpath

Block height on the backend main chain.

Response

200OK

Block hash at the requested height.

400Bad Request

Public API error (JSON).

401Unauthorized

Missing or invalid API key (plain text).

Get a block hash by height.

curl -X GET 'https://ethw-blockbook.nownodes.io/api/v2/block-index/{height}'

const response = await fetch('https://ethw-blockbook.nownodes.io/api/v2/block-index/{height}', {
  method: 'GET',
});

const data = await response.json();

require 'net/http'
require 'json'

uri = URI('https://ethw-blockbook.nownodes.io/api/v2/block-index/{height}')
request = Net::HTTP::Get.new(uri)

response = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |http| http.request(request) }
data = JSON.parse(response.body)

import requests

response = requests.get('https://ethw-blockbook.nownodes.io/api/v2/block-index/{height}')
data = response.json()

const response = await fetch('https://ethw-blockbook.nownodes.io/api/v2/block-index/{height}', {
  method: 'GET',
});

const data = await response.json();

const endpoint = "https://ethw-blockbook.nownodes.io/api/v2/block-index/{height}";
const apiKey = "YOUR_API_KEY";

async function nownodesRequest(payload) {
  const response = await fetch(endpoint, {
    method: "GET",
    headers: {
      "Content-Type": "application/json",
      "api-key": apiKey,
    },
    body: JSON.stringify(payload),
  });

  return response.json();
}

const result = await nownodesRequest({});
console.log(result);

const response = await fetch('https://ethw-blockbook.nownodes.io/api/v2/block-index/{height}', {
  method: 'GET',
});

const data = await response.json();

import requests

response = requests.get('https://ethw-blockbook.nownodes.io/api/v2/block-index/{height}')
data = response.json()

require 'net/http'
require 'json'

uri = URI('https://ethw-blockbook.nownodes.io/api/v2/block-index/{height}')
request = Net::HTTP::Get.new(uri)

response = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |http| http.request(request) }
data = JSON.parse(response.body)

{
  "blockHash": "0x88e96d4537bea4d9c05d12549907b32561d3bf31f45aae734cdc119f13406cb6"
}

{
  "blockHash": ""
}

Unknown API_key