The code is copied from https://www.npmjs.com/package/@evmexplorer/blockscout export async function fetchAddressTransactions( address: string, parameters?: string, chainId?: number, ): Promise<AddressTransactionsBlockscout> { const chainProvider: string = getChainProviderBlockscout(chainId); let query: string = ''; if (parameters) { query = https://${chainProvider}/api/v2/addresses/${address}/transactions?${parameters} ; } if (!parameters) { query = https://${chainProvider}/api/v2/addresses/${address}/transactions ; } const response: Response = await fetch(query); const body = (await response.json()) as AddressTransactionsBlockscout; if (body) return body; throw new Error('no transactions'); } const transactions = await fetchAddressTransactions( '0x398eC7346DcD622eDc5ae82352F02bE94C62d119', ); const array1: string[] = []; const map1 = transactions?.items?.map((x) => { array1.push(x.hash); }); console.log([...new Set(array1)].length); const transactionsSecondPage = await fetchAddressTransactions( '0x398eC7346DcD622eDc5ae82352F02bE94C62d119', ?block_number=${transactions?.next_page_params?.block_number}&index=${transactions?.next_page_params?.index}&items_count=${transactions?.next_page_params?.items_count} , ); const array2: string[] = []; const map2 = transactionsSecondPage?.items?.map((x) => { array2.push(x.hash); }); console.log([...new Set(array2)].length); console.log([...new Set(array1.concat(array2))].length); The result is that there are 20 duplicate entries