curl --request PUT \
  --url https://api.hit-pay.com/v1/invoices/{invoice_id} \
  --header 'Content-Type: application/json' \
  --header 'X-BUSINESS-API-KEY: <x-business-api-key>' \
  --data '
{
  "invoice_date": "<string>",
  "currency": "<string>",
  "amount": 123,
  "payment_by": "<string>",
  "customer": {
    "name": "<string>",
    "email": "<string>",
    "address": {
      "name": "160 Paya Lebar Road 07-08 Orion Industrial ",
      "city": "Singapore",
      "state": "Singapore",
      "postal_code": "367903",
      "country": "sg"
    }
  },
  "customer_id": "<string>",
  "due_date": "<string>",
  "auto_invoice_number": "<string>",
  "invoice_number": "<string>",
  "payment_methods": [
    "paynow_online"
  ],
  "subtotal": 123,
  "tax_setting": "<string>",
  "send_email": 0,
  "webhook": "<string>",
  "reference": "<string>",
  "footer": "<string>",
  "allow_partial_payments": 0,
  "partial_payments": [
    {
      "amount": 0,
      "due_date": "<string>"
    }
  ],
  "products": [
    {
      "product_id": "<string>",
      "quantity": "<string>",
      "variation_id": "<string>",
      "discount": "<string>"
    }
  ],
  "stackable_discounts": [
    {
      "name": "<string>",
      "discount": "<string>",
      "percentage_discount": "<string>",
      "order": "<string>"
    }
  ],
  "recipients": [
    {
      "email": "<string>",
      "customer_id": "<string>"
    }
  ]
}
'

import requests

url = "https://api.hit-pay.com/v1/invoices/{invoice_id}"

payload = {
    "invoice_date": "<string>",
    "currency": "<string>",
    "amount": 123,
    "payment_by": "<string>",
    "customer": {
        "name": "<string>",
        "email": "<string>",
        "address": {
            "name": "160 Paya Lebar Road 07-08 Orion Industrial ",
            "city": "Singapore",
            "state": "Singapore",
            "postal_code": "367903",
            "country": "sg"
        }
    },
    "customer_id": "<string>",
    "due_date": "<string>",
    "auto_invoice_number": "<string>",
    "invoice_number": "<string>",
    "payment_methods": ["paynow_online"],
    "subtotal": 123,
    "tax_setting": "<string>",
    "send_email": 0,
    "webhook": "<string>",
    "reference": "<string>",
    "footer": "<string>",
    "allow_partial_payments": 0,
    "partial_payments": [
        {
            "amount": 0,
            "due_date": "<string>"
        }
    ],
    "products": [
        {
            "product_id": "<string>",
            "quantity": "<string>",
            "variation_id": "<string>",
            "discount": "<string>"
        }
    ],
    "stackable_discounts": [
        {
            "name": "<string>",
            "discount": "<string>",
            "percentage_discount": "<string>",
            "order": "<string>"
        }
    ],
    "recipients": [
        {
            "email": "<string>",
            "customer_id": "<string>"
        }
    ]
}
headers = {
    "X-BUSINESS-API-KEY": "<x-business-api-key>",
    "Content-Type": "application/json"
}

response = requests.put(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'PUT',
  headers: {
    'X-BUSINESS-API-KEY': '<x-business-api-key>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    invoice_date: '<string>',
    currency: '<string>',
    amount: 123,
    payment_by: '<string>',
    customer: {
      name: '<string>',
      email: '<string>',
      address: {
        name: '160 Paya Lebar Road 07-08 Orion Industrial ',
        city: 'Singapore',
        state: 'Singapore',
        postal_code: '367903',
        country: 'sg'
      }
    },
    customer_id: '<string>',
    due_date: '<string>',
    auto_invoice_number: '<string>',
    invoice_number: '<string>',
    payment_methods: ['paynow_online'],
    subtotal: 123,
    tax_setting: '<string>',
    send_email: 0,
    webhook: '<string>',
    reference: '<string>',
    footer: '<string>',
    allow_partial_payments: 0,
    partial_payments: [{amount: 0, due_date: '<string>'}],
    products: [
      {
        product_id: '<string>',
        quantity: '<string>',
        variation_id: '<string>',
        discount: '<string>'
      }
    ],
    stackable_discounts: [
      {
        name: '<string>',
        discount: '<string>',
        percentage_discount: '<string>',
        order: '<string>'
      }
    ],
    recipients: [{email: '<string>', customer_id: '<string>'}]
  })
};

fetch('https://api.hit-pay.com/v1/invoices/{invoice_id}', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.hit-pay.com/v1/invoices/{invoice_id}",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "PUT",
  CURLOPT_POSTFIELDS => json_encode([
    'invoice_date' => '<string>',
    'currency' => '<string>',
    'amount' => 123,
    'payment_by' => '<string>',
    'customer' => [
        'name' => '<string>',
        'email' => '<string>',
        'address' => [
                'name' => '160 Paya Lebar Road 07-08 Orion Industrial ',
                'city' => 'Singapore',
                'state' => 'Singapore',
                'postal_code' => '367903',
                'country' => 'sg'
        ]
    ],
    'customer_id' => '<string>',
    'due_date' => '<string>',
    'auto_invoice_number' => '<string>',
    'invoice_number' => '<string>',
    'payment_methods' => [
        'paynow_online'
    ],
    'subtotal' => 123,
    'tax_setting' => '<string>',
    'send_email' => 0,
    'webhook' => '<string>',
    'reference' => '<string>',
    'footer' => '<string>',
    'allow_partial_payments' => 0,
    'partial_payments' => [
        [
                'amount' => 0,
                'due_date' => '<string>'
        ]
    ],
    'products' => [
        [
                'product_id' => '<string>',
                'quantity' => '<string>',
                'variation_id' => '<string>',
                'discount' => '<string>'
        ]
    ],
    'stackable_discounts' => [
        [
                'name' => '<string>',
                'discount' => '<string>',
                'percentage_discount' => '<string>',
                'order' => '<string>'
        ]
    ],
    'recipients' => [
        [
                'email' => '<string>',
                'customer_id' => '<string>'
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "X-BUSINESS-API-KEY: <x-business-api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.hit-pay.com/v1/invoices/{invoice_id}"

	payload := strings.NewReader("{\n  \"invoice_date\": \"<string>\",\n  \"currency\": \"<string>\",\n  \"amount\": 123,\n  \"payment_by\": \"<string>\",\n  \"customer\": {\n    \"name\": \"<string>\",\n    \"email\": \"<string>\",\n    \"address\": {\n      \"name\": \"160 Paya Lebar Road 07-08 Orion Industrial \",\n      \"city\": \"Singapore\",\n      \"state\": \"Singapore\",\n      \"postal_code\": \"367903\",\n      \"country\": \"sg\"\n    }\n  },\n  \"customer_id\": \"<string>\",\n  \"due_date\": \"<string>\",\n  \"auto_invoice_number\": \"<string>\",\n  \"invoice_number\": \"<string>\",\n  \"payment_methods\": [\n    \"paynow_online\"\n  ],\n  \"subtotal\": 123,\n  \"tax_setting\": \"<string>\",\n  \"send_email\": 0,\n  \"webhook\": \"<string>\",\n  \"reference\": \"<string>\",\n  \"footer\": \"<string>\",\n  \"allow_partial_payments\": 0,\n  \"partial_payments\": [\n    {\n      \"amount\": 0,\n      \"due_date\": \"<string>\"\n    }\n  ],\n  \"products\": [\n    {\n      \"product_id\": \"<string>\",\n      \"quantity\": \"<string>\",\n      \"variation_id\": \"<string>\",\n      \"discount\": \"<string>\"\n    }\n  ],\n  \"stackable_discounts\": [\n    {\n      \"name\": \"<string>\",\n      \"discount\": \"<string>\",\n      \"percentage_discount\": \"<string>\",\n      \"order\": \"<string>\"\n    }\n  ],\n  \"recipients\": [\n    {\n      \"email\": \"<string>\",\n      \"customer_id\": \"<string>\"\n    }\n  ]\n}")

	req, _ := http.NewRequest("PUT", url, payload)

	req.Header.Add("X-BUSINESS-API-KEY", "<x-business-api-key>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.put("https://api.hit-pay.com/v1/invoices/{invoice_id}")
  .header("X-BUSINESS-API-KEY", "<x-business-api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"invoice_date\": \"<string>\",\n  \"currency\": \"<string>\",\n  \"amount\": 123,\n  \"payment_by\": \"<string>\",\n  \"customer\": {\n    \"name\": \"<string>\",\n    \"email\": \"<string>\",\n    \"address\": {\n      \"name\": \"160 Paya Lebar Road 07-08 Orion Industrial \",\n      \"city\": \"Singapore\",\n      \"state\": \"Singapore\",\n      \"postal_code\": \"367903\",\n      \"country\": \"sg\"\n    }\n  },\n  \"customer_id\": \"<string>\",\n  \"due_date\": \"<string>\",\n  \"auto_invoice_number\": \"<string>\",\n  \"invoice_number\": \"<string>\",\n  \"payment_methods\": [\n    \"paynow_online\"\n  ],\n  \"subtotal\": 123,\n  \"tax_setting\": \"<string>\",\n  \"send_email\": 0,\n  \"webhook\": \"<string>\",\n  \"reference\": \"<string>\",\n  \"footer\": \"<string>\",\n  \"allow_partial_payments\": 0,\n  \"partial_payments\": [\n    {\n      \"amount\": 0,\n      \"due_date\": \"<string>\"\n    }\n  ],\n  \"products\": [\n    {\n      \"product_id\": \"<string>\",\n      \"quantity\": \"<string>\",\n      \"variation_id\": \"<string>\",\n      \"discount\": \"<string>\"\n    }\n  ],\n  \"stackable_discounts\": [\n    {\n      \"name\": \"<string>\",\n      \"discount\": \"<string>\",\n      \"percentage_discount\": \"<string>\",\n      \"order\": \"<string>\"\n    }\n  ],\n  \"recipients\": [\n    {\n      \"email\": \"<string>\",\n      \"customer_id\": \"<string>\"\n    }\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.hit-pay.com/v1/invoices/{invoice_id}")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Put.new(url)
request["X-BUSINESS-API-KEY"] = '<x-business-api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"invoice_date\": \"<string>\",\n  \"currency\": \"<string>\",\n  \"amount\": 123,\n  \"payment_by\": \"<string>\",\n  \"customer\": {\n    \"name\": \"<string>\",\n    \"email\": \"<string>\",\n    \"address\": {\n      \"name\": \"160 Paya Lebar Road 07-08 Orion Industrial \",\n      \"city\": \"Singapore\",\n      \"state\": \"Singapore\",\n      \"postal_code\": \"367903\",\n      \"country\": \"sg\"\n    }\n  },\n  \"customer_id\": \"<string>\",\n  \"due_date\": \"<string>\",\n  \"auto_invoice_number\": \"<string>\",\n  \"invoice_number\": \"<string>\",\n  \"payment_methods\": [\n    \"paynow_online\"\n  ],\n  \"subtotal\": 123,\n  \"tax_setting\": \"<string>\",\n  \"send_email\": 0,\n  \"webhook\": \"<string>\",\n  \"reference\": \"<string>\",\n  \"footer\": \"<string>\",\n  \"allow_partial_payments\": 0,\n  \"partial_payments\": [\n    {\n      \"amount\": 0,\n      \"due_date\": \"<string>\"\n    }\n  ],\n  \"products\": [\n    {\n      \"product_id\": \"<string>\",\n      \"quantity\": \"<string>\",\n      \"variation_id\": \"<string>\",\n      \"discount\": \"<string>\"\n    }\n  ],\n  \"stackable_discounts\": [\n    {\n      \"name\": \"<string>\",\n      \"discount\": \"<string>\",\n      \"percentage_discount\": \"<string>\",\n      \"order\": \"<string>\"\n    }\n  ],\n  \"recipients\": [\n    {\n      \"email\": \"<string>\",\n      \"customer_id\": \"<string>\"\n    }\n  ]\n}"

response = http.request(request)
puts response.read_body

This response has no body data.