curl --request POST \
  --url https://api.meetcampfire.com/rev/api/v1/contracts/{id}/link-invoice \
  --header 'Content-Type: application/json' \
  --data '{
  "invoice": 123
}'

import requests

url = "https://api.meetcampfire.com/rev/api/v1/contracts/{id}/link-invoice"

payload = { "invoice": 123 }
headers = {"Content-Type": "application/json"}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({invoice: 123})
};

fetch('https://api.meetcampfire.com/rev/api/v1/contracts/{id}/link-invoice', 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.meetcampfire.com/rev/api/v1/contracts/{id}/link-invoice",
  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([
    'invoice' => 123
  ]),
  CURLOPT_HTTPHEADER => [
    "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://api.meetcampfire.com/rev/api/v1/contracts/{id}/link-invoice"

	payload := strings.NewReader("{\n  \"invoice\": 123\n}")

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

	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://api.meetcampfire.com/rev/api/v1/contracts/{id}/link-invoice")
  .header("Content-Type", "application/json")
  .body("{\n  \"invoice\": 123\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.meetcampfire.com/rev/api/v1/contracts/{id}/link-invoice")

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

request = Net::HTTP::Post.new(url)
request["Content-Type"] = 'application/json'
request.body = "{\n  \"invoice\": 123\n}"

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

{
  "id": 123,
  "contract": 123,
  "contract_name": "<string>",
  "contract_number": "<string>",
  "entity": 123,
  "entity_name": "",
  "client": 123,
  "client_name": "",
  "invoice": 123,
  "journal_entry": 123,
  "journal_entry_number": "<string>",
  "issue_date": "2023-12-25",
  "tax_rate_name": "",
  "anrok_connection_name": "",
  "avalara_connection_name": "",
  "sphere_connection_name": "",
  "stripe_connection_name": "",
  "subtotal": 0,
  "is_linked": true,
  "needs_live_date_fx_recalc": true,
  "lines": [
    {
      "id": 123,
      "invoice": 123,
      "product_name": "",
      "department_name": "",
      "created_at": "2023-11-07T05:31:56Z",
      "last_modified_at": "2023-11-07T05:31:56Z",
      "contract_line": 123,
      "product": 123,
      "description": "<string>",
      "service_start": "2023-12-25",
      "service_end": "2023-12-25",
      "currency": "<string>",
      "quantity": 0,
      "rate": 0,
      "amount": 0,
      "tax": 0,
      "tax_description": "<string>",
      "discount": 0,
      "department": 123,
      "tags": [
        123
      ]
    }
  ],
  "created_at": "2023-11-07T05:31:56Z",
  "last_modified_at": "2023-11-07T05:31:56Z",
  "ordinal": 1073741823,
  "invoice_number": "<string>",
  "status": "DRAFT",
  "accounting_date": "2023-12-25",
  "due_date": "2023-12-25",
  "payment_term": 123,
  "bill_to_snapshot": "<unknown>",
  "currency": "<string>",
  "purchase_order_number": "<string>",
  "period_start": "2023-12-25",
  "period_end": "2023-12-25",
  "shipping_date": "2023-12-25",
  "location_of_sale": "<string>",
  "vat_number": "<string>",
  "billing_address": "<string>",
  "billing_addressee": "<string>",
  "shipping_address": "<string>",
  "shipping_addressee": "<string>",
  "message_on_invoice": "<string>",
  "tax_rate": 123,
  "anrok_connection": 123,
  "avalara_connection": 123,
  "sphere_connection": 123,
  "stripe_connection": 123,
  "use_stripe_auto_bill": true,
  "discount": 0,
  "total_amount": 0
}