JSON Response

JSON Response

Hello,

Can someone tell me what I'm doing wrong, I want to fetch the tax_total from Zoho Books using a geturl function. The function which I made is written below:

//API Books
headerMap = Map:String({"Authorization":"Zoho-authtoken <auth_token>"});
x = getUrl(" https://books.zoho.com/api/v3/invoices/" + X + "?organization_id=6231230351",headerMap);
//Fetch JSON for MultiLine
input.Response_Books_Get = x;
//Get Total_VAT
response = x.getJSON("invoice");
result = response.getJSON("tax_total");
input.Tax_Total_Tekst = result;

The response I get and which is put into the field "input.Response_Books_Get" so I suppose the API is working fine but how do I fetch the value Tax Total:

{"code":0,"invoice":{"date":"2018-05-05","notes":"","can_send_in_mail":false,"zcrm_potential_id":"","documents":[],"client_viewed_time":"","discount_amount":0.0,"is_client_review_settings_enabled":true,"discount":0.0,"taxes":[{"tax_amount":12.6,"tax_name":"BTW hoog tarief (21%)"}],"billing_address":{"zip":"4201JA","country":"Nederland","address":"Haarstraat 25","city":"Gorinchem","phone":"","attention":"","street2":"","state":"","fax":""},"line_items":[{"bcy_rate":60.0,"salesorder_item_id":"","line_item_id":"957028000001104029","documents":[],"item_type":"sales","description":"","discount":0.0,"item_order":0,"bill_item_id":"","project_id":"","rate":60.0,"account_name":"Verkoop","bill_id":"","quantity":1.0,"item_id":"957028000001099005","expense_receipt_name":"","tax_name":"BTW hoog tarief","item_total":60.0,"item_custom_fields":[],"tax_id":"957028000000061050","tags":[],"unit":"","account_id":"957028000000000388","tax_type":"tax","time_entry_ids":[],"name":"Administratieve dienstverlening","tax_percentage":21,"expense_id":""}],"balance":72.6,"terms":"","credits_applied":0.0,"invoice_id":"957028000001104027","contact_category":"","template_type":"standard","invoice_number":"2018000010","recurring_invoice_id":"","contact_persons":["957028000000096029"],"payment_options":{"payment_gateways":[{"configured":true,"can_show_billing_address":false,"additional_field1":"standard","is_bank_account_applicable":false,"gateway_name":"paypal"}]},"stop_reminder_until_payment_expected_date":false,"created_time":"2018-05-05T07:39:04+0200","sub_total_inclusive_of_tax":0.0,"exchange_rate":1.0,"is_inclusive_tax":false,"approver_id":"","custom_fields":[],"estimate_id":"","last_payment_date":"","merchant_name":"","reference_number":"","price_precision":2,"is_autobill_enabled":false,"payment_discount":0.0,"zcrm_potential_name":"","adjustment":0.0,"created_by_id":"957028000000061001","page_height":"11.69in","status":"draft","tax_total":12.6,"is_discount_before_tax":true,"is_viewed_by_client":false,"write_off_amount":0.0,"attachment_name":"","salesorder_id":"","ach_payment_initiated":false,"last_reminder_sent_date":"","merchant_id":"","payment_terms":0,"currency_code":"EUR","page_width":"8.27in","total":72.6,"tax_amount_withheld":0.0,"custom_field_hash":{},"shipping_address":{"zip":"","country":"","address":"","city":"","phone":"","attention":"","street2":"","state":"","fax":""},"next_reminder_date_formatted":"","adjustment_description":"Aanpassing","orientation":"portrait","discount_applied_on_amount":0.0,"last_modified_time":"2018-05-05T07:39:04+0200","currency_symbol":"\u20ac","due_date":"2018-05-05","submitter_id":"","shipping_bills":[],"payment_expected_date":"","unused_retainer_payments":0.0,"discount_type":"entity_level","is_emailed":false,"reminders_sent":0,"transaction_rounding_type":"no_rounding","salesperson_name":"Erwin Fennema","contact_persons_details":[{"phone":"0183-201077","mobile":"","last_name":"","contact_person_id":"957028000000096029","photo_url":" d Template","salesperson_id":"957028000001099164","shipping_charge":0.0,"payment_made":0.0,"schedule_time":"","sub_total":60.0,"template_id":"957028000000017001","customer_name":"FIDURO","allow_partial_payments":true,"customer_id":"957028000000096027","currency_id":"957028000000000109","invoice_url":" https://books.zoho.com/portal/blabla/secure?CInvoiceID=2-14618b1e0af9b3b2a0ea95b06d7563e133a51ad597df1aa07aff861123123a5532a52dcb617ce57b9731ffe4edd987e95cd9bff9df56e04 ","payment_terms_label":"Verschuldigd bij ontvangst","payment_reminder_enabled":true},"message":"success"}