curl -sS -X POST https://api-frequency.n.dwellir.com/1a4a621f-4f4a-432f-bcc3-76e741750166 \
  -H 'Content-Type: application/json' \
  -d '{"id":1,"jsonrpc":"2.0","method":"chain_getBlockHash","params":[0]}'

import { ApiPromise, WsProvider } from '@polkadot/api';

const provider = new WsProvider('wss://api-frequency.n.dwellir.com/1a4a621f-4f4a-432f-bcc3-76e741750166');
const api = await ApiPromise.create({ provider });
const hash = await api.rpc.chain.getBlockHash(0);
console.log(hash.toHex());

from substrateinterface import SubstrateInterface

substrate = SubstrateInterface(url='wss://api-frequency.n.dwellir.com/1a4a621f-4f4a-432f-bcc3-76e741750166')
block_hash = substrate.get_block_hash(block_id=0)
print(block_hash)

package main

import (
  "fmt"
  gsrpc "github.com/centrifuge/go-substrate-rpc-client/v4"
  "github.com/centrifuge/go-substrate-rpc-client/v4/types"
)

func main() {
  api, err := gsrpc.NewSubstrateAPI("wss://api-frequency.n.dwellir.com/1a4a621f-4f4a-432f-bcc3-76e741750166")
  if err != nil { panic(err) }
  var h types.Hash
  h, err = api.RPC.Chain.GetBlockHash(0)
  if err != nil { panic(err) }
  fmt.Println(h.Hex())
}