curl --request POST \
  --url https://{workspace}.spreesuite.com/billspree/connections/make-connections \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "method": "Create",
  "action": "Create Subscription",
  "apiVersion": "v2",
  "batchUpload": false,
  "connection": {
    "serviceCode": "DEMO-001",
    "tariffCode": "DemoPlan",
    "batchCode": null,
    "addonTariffLabels": [],
    "connectionRefNo": null,
    "description": null,
    "postType": "Post Subscription",
    "paymentMethod": null,
    "projectName": null,
    "connectionInputs": [
      {
        "name": "MeterNo",
        "value": "12345"
      }
    ],
    "meteredConnectionInputs": [],
    "unmeteredInputs": [],
    "meters": [],
    "accounts": [],
    "users": [],
    "variants": [],
    "address": null
  }
}
'

import requests

url = "https://{workspace}.spreesuite.com/billspree/connections/make-connections"

payload = {
    "method": "Create",
    "action": "Create Subscription",
    "apiVersion": "v2",
    "batchUpload": False,
    "connection": {
        "serviceCode": "DEMO-001",
        "tariffCode": "DemoPlan",
        "batchCode": None,
        "addonTariffLabels": [],
        "connectionRefNo": None,
        "description": None,
        "postType": "Post Subscription",
        "paymentMethod": None,
        "projectName": None,
        "connectionInputs": [
            {
                "name": "MeterNo",
                "value": "12345"
            }
        ],
        "meteredConnectionInputs": [],
        "unmeteredInputs": [],
        "meters": [],
        "accounts": [],
        "users": [],
        "variants": [],
        "address": None
    }
}
headers = {
    "Authorization": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    method: 'Create',
    action: 'Create Subscription',
    apiVersion: 'v2',
    batchUpload: false,
    connection: {
      serviceCode: 'DEMO-001',
      tariffCode: 'DemoPlan',
      batchCode: null,
      addonTariffLabels: [],
      connectionRefNo: null,
      description: null,
      postType: 'Post Subscription',
      paymentMethod: null,
      projectName: null,
      connectionInputs: [{name: 'MeterNo', value: '12345'}],
      meteredConnectionInputs: [],
      unmeteredInputs: [],
      meters: [],
      accounts: [],
      users: [],
      variants: [],
      address: null
    }
  })
};

fetch('https://{workspace}.spreesuite.com/billspree/connections/make-connections', 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://{workspace}.spreesuite.com/billspree/connections/make-connections",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'method' => 'Create',
    'action' => 'Create Subscription',
    'apiVersion' => 'v2',
    'batchUpload' => false,
    'connection' => [
        'serviceCode' => 'DEMO-001',
        'tariffCode' => 'DemoPlan',
        'batchCode' => null,
        'addonTariffLabels' => [
                
        ],
        'connectionRefNo' => null,
        'description' => null,
        'postType' => 'Post Subscription',
        'paymentMethod' => null,
        'projectName' => null,
        'connectionInputs' => [
                [
                                'name' => 'MeterNo',
                                'value' => '12345'
                ]
        ],
        'meteredConnectionInputs' => [
                
        ],
        'unmeteredInputs' => [
                
        ],
        'meters' => [
                
        ],
        'accounts' => [
                
        ],
        'users' => [
                
        ],
        'variants' => [
                
        ],
        'address' => null
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: <api-key>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($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://{workspace}.spreesuite.com/billspree/connections/make-connections"

	payload := strings.NewReader("{\n  \"method\": \"Create\",\n  \"action\": \"Create Subscription\",\n  \"apiVersion\": \"v2\",\n  \"batchUpload\": false,\n  \"connection\": {\n    \"serviceCode\": \"DEMO-001\",\n    \"tariffCode\": \"DemoPlan\",\n    \"batchCode\": null,\n    \"addonTariffLabels\": [],\n    \"connectionRefNo\": null,\n    \"description\": null,\n    \"postType\": \"Post Subscription\",\n    \"paymentMethod\": null,\n    \"projectName\": null,\n    \"connectionInputs\": [\n      {\n        \"name\": \"MeterNo\",\n        \"value\": \"12345\"\n      }\n    ],\n    \"meteredConnectionInputs\": [],\n    \"unmeteredInputs\": [],\n    \"meters\": [],\n    \"accounts\": [],\n    \"users\": [],\n    \"variants\": [],\n    \"address\": null\n  }\n}")

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

	req.Header.Add("Authorization", "<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.post("https://{workspace}.spreesuite.com/billspree/connections/make-connections")
  .header("Authorization", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"method\": \"Create\",\n  \"action\": \"Create Subscription\",\n  \"apiVersion\": \"v2\",\n  \"batchUpload\": false,\n  \"connection\": {\n    \"serviceCode\": \"DEMO-001\",\n    \"tariffCode\": \"DemoPlan\",\n    \"batchCode\": null,\n    \"addonTariffLabels\": [],\n    \"connectionRefNo\": null,\n    \"description\": null,\n    \"postType\": \"Post Subscription\",\n    \"paymentMethod\": null,\n    \"projectName\": null,\n    \"connectionInputs\": [\n      {\n        \"name\": \"MeterNo\",\n        \"value\": \"12345\"\n      }\n    ],\n    \"meteredConnectionInputs\": [],\n    \"unmeteredInputs\": [],\n    \"meters\": [],\n    \"accounts\": [],\n    \"users\": [],\n    \"variants\": [],\n    \"address\": null\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://{workspace}.spreesuite.com/billspree/connections/make-connections")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"method\": \"Create\",\n  \"action\": \"Create Subscription\",\n  \"apiVersion\": \"v2\",\n  \"batchUpload\": false,\n  \"connection\": {\n    \"serviceCode\": \"DEMO-001\",\n    \"tariffCode\": \"DemoPlan\",\n    \"batchCode\": null,\n    \"addonTariffLabels\": [],\n    \"connectionRefNo\": null,\n    \"description\": null,\n    \"postType\": \"Post Subscription\",\n    \"paymentMethod\": null,\n    \"projectName\": null,\n    \"connectionInputs\": [\n      {\n        \"name\": \"MeterNo\",\n        \"value\": \"12345\"\n      }\n    ],\n    \"meteredConnectionInputs\": [],\n    \"unmeteredInputs\": [],\n    \"meters\": [],\n    \"accounts\": [],\n    \"users\": [],\n    \"variants\": [],\n    \"address\": null\n  }\n}"

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

{
  "success": true,
  "statusCode": 200,
  "message": "Request Succeeded.",
  "error": null,
  "data": {}
}