List block headers

POST

https://sei-tendermint.nownodes.io/

Authorizations

ApiKeyAuthApiKeyAuth

api-key string

NOWNodes API key passed in the api-key header.

Returns up to 20 block headers between the requested minimum and maximum heights in descending order.

Body

application/json

JSON-RPC request for blockchain.

jsonrpcstring2.0required

JSON-RPC protocol version.

idintegerrequired

Client request identifier.

methodstringblockchainrequired

RPC method name.

paramsobjectrequired

Parameters accepted by blockchain.

Show child attributes

minHeightstring

Lowest block height to include.

maxHeightstring

Highest block height to include.

Response

200OK

Response returned by the live Sei endpoint.

400Bad Request

Invalid JSON-RPC request.

List block headers

curl -X POST 'https://sei-tendermint.nownodes.io/' \
  -H 'Content-Type: application/json' \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "blockchain",
    "params": {
      "minHeight": "233842495",
      "maxHeight": "233842496"
    }
  }'

import { JsonRpcProvider } from "ethers";

const provider = new JsonRpcProvider("https://sei-tendermint.nownodes.io/");
const result = await provider.send("blockchain", {
  "minHeight": "233842495",
  "maxHeight": "233842496"
});
console.log(result);

require 'eth'
require 'json'
require 'net/http'

uri = URI('https://sei-tendermint.nownodes.io/')
request = Net::HTTP::Post.new(uri)
request['Content-Type'] = 'application/json'
request.body = '{
  "jsonrpc": "2.0",
  "method": "blockchain",
  "params": {
    "minHeight": "233842495",
    "maxHeight": "233842496"
  },
  "id": 1
}'

response = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) do |http|
  http.request(request)
end

puts JSON.parse(response.body)

from web3 import Web3

w3 = Web3(Web3.HTTPProvider("https://sei-tendermint.nownodes.io/"))
response = w3.provider.make_request("blockchain", {
  "minHeight": "233842495",
  "maxHeight": "233842496"
})
print(response)

import { createPublicClient, http } from "viem";

const client = createPublicClient({
  transport: http("https://sei-tendermint.nownodes.io/"),
});

const result = await client.request({
  method: "blockchain",
  params: {
  "minHeight": "233842495",
  "maxHeight": "233842496"
},
});

console.log(result);

const endpoint = "https://sei-tendermint.nownodes.io/";
const apiKey = "YOUR_API_KEY";

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

  return response.json();
}

const result = await nownodesRequest({ jsonrpc: "2.0", method: "blockchain", params: {
  "minHeight": "233842495",
  "maxHeight": "233842496"
}, id: 1 });
console.log(result);

const response = await fetch('https://sei-tendermint.nownodes.io/', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
      "jsonrpc": "2.0",
      "id": 1,
      "method": "blockchain",
      "params": {
        "minHeight": "233842495",
        "maxHeight": "233842496"
      }
    }),
});

const data = await response.json();

import requests

payload = {
  "jsonrpc": "2.0",
  "id": 1,
  "method": "blockchain",
  "params": {
    "minHeight": "233842495",
    "maxHeight": "233842496"
  }
}

response = requests.post('https://sei-tendermint.nownodes.io/', json=payload)
data = response.json()

require 'net/http'
require 'json'

uri = URI('https://sei-tendermint.nownodes.io/')
request = Net::HTTP::Post.new(uri)
request['Content-Type'] = 'application/json'
request.body = '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "blockchain",
    "params": {
      "minHeight": "233842495",
      "maxHeight": "233842496"
    }
  }'

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

Request Body

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "blockchain",
  "params": {
    "minHeight": "233842495",
    "maxHeight": "233842496"
  }
}

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "last_height": "233842529",
    "block_metas": [
      {
        "block_id": {
          "hash": "5C7A393701F191D58B78DF6C59614CEE6D57435F3811B5C94035CC9F3D71F591",
          "parts": {
            "total": 1,
            "hash": "475A71BBC2BC5C16701C629FDADD0C41E425D734E6CCF58A8771112E3C11A356"
          }
        },
        "block_size": "5683",
        "header": {
          "version": {
            "block": "11",
            "app": "0"
          },
          "chain_id": "pacific-1",
          "height": "233842496",
          "time": "2026-09-24T11:14:35.632451401Z",
          "last_block_id": {
            "hash": "2AF8634643C78442DC5CB64616133DE832B352F5DCB434A2B313EB813CA19130",
            "parts": {
              "total": 1,
              "hash": "B7775A12F23AF0B7393C5F12B87EE1E0768C42691276CD55F3C1733914410883"
            }
          },
          "last_commit_hash": "2D0D9FD90DC60D574527CDE4D2DA890C8EAFC825A6F83B0E2CD35B029429AB73",
          "data_hash": "3313785EB9F9004087F27B103DDEEF52F9AEDE0B09CD97D885973EB7181BAAA2",
          "validators_hash": "89F6363C479F2CFE9CF318CF5713B9DB2346AAB180F36116D4115F960F4A46CC",
          "next_validators_hash": "89F6363C479F2CFE9CF318CF5713B9DB2346AAB180F36116D4115F960F4A46CC",
          "consensus_hash": "1E24CCFFDC895ED64854A10BA401678BE9403E3CCD8752EEF8A901BB7EA07A20",
          "app_hash": "9AB1E7C926ED23F439ABC5803833097D5181220BE3F3BBAF26D0C899D45B3E38",
          "last_results_hash": "B073B1F15BF89CA2721B9A92608D2314F780877DAA2B86D2A67D09830DF8B67D",
          "evidence_hash": "E3B0C44298FC1C149AFBF4C8996FB92427AE41E4649B934CA495991B7852B855",
          "proposer_address": "00D66A1CB50A2473D8F011D369ADB117A527072D"
        },
        "num_txs": "2"
      }
    ]
  }
}

{
  "jsonrpc": "2.0",
  "id": 1,
  "error": {
    "code": -32602,
    "message": "Invalid params"
  }
}