Get a block hash by height.

GET

https://optimism-index.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.

Parameters

heightinteger>= 0requiredpath

Block height on the backend main chain.

Response

200OK

Block hash at the requested height.

401Unauthorized

Unauthorized: API key is present but rejected by the NOWNodes gateway.

405Method Not Allowed

Method Not Allowed. Returned by the NOWNodes gateway for malformed or unsupported gateway-level requests.

422Unprocessable Entity

Missing API key. The NOWNodes gateway returns plain text for this error.

default

Public API error.

Get a block hash by height.

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

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

const data = await response.json();

require 'net/http'
require 'json'

uri = URI('https://optimism-index.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://optimism-index.nownodes.io/api/v2/block-index/{height}')
data = response.json()

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

const data = await response.json();

const endpoint = "https://optimism-index.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://optimism-index.nownodes.io/api/v2/block-index/{height}', {
  method: 'GET',
});

const data = await response.json();

import requests

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

require 'net/http'
require 'json'

uri = URI('https://optimism-index.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": "0x8dd378bdf3dd5d90a1303960f7185b4f131ade57192ee98750f6098c4c4ba071"
}

Unknown API_key

Method Not Allowed

Missing API_key

{
  "error": "Block height out of range"
}