curl --request POST \
  --url https://api.upwell.com/api/rest/invoices/{invoiceId}/documents \
  --header 'Content-Type: application/json' \
  --data '
{
  "input": {
    "base64": "<string>",
    "filename": "<string>",
    "mimeType": "<string>",
    "sourceSystem": "<string>",
    "sourceSystemId": "<string>",
    "type": "<string>",
    "visibleToCarrier": true,
    "visibleToCustomer": true
  },
  "invoiceId": "<string>"
}
'

import requests

url = "https://api.upwell.com/api/rest/invoices/{invoiceId}/documents"

payload = {
    "input": {
        "base64": "<string>",
        "filename": "<string>",
        "mimeType": "<string>",
        "sourceSystem": "<string>",
        "sourceSystemId": "<string>",
        "type": "<string>",
        "visibleToCarrier": True,
        "visibleToCustomer": True
    },
    "invoiceId": "<string>"
}
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({
    input: {
      base64: '<string>',
      filename: '<string>',
      mimeType: '<string>',
      sourceSystem: '<string>',
      sourceSystemId: '<string>',
      type: '<string>',
      visibleToCarrier: true,
      visibleToCustomer: true
    },
    invoiceId: '<string>'
  })
};

fetch('https://api.upwell.com/api/rest/invoices/{invoiceId}/documents', 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.upwell.com/api/rest/invoices/{invoiceId}/documents",
  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([
    'input' => [
        'base64' => '<string>',
        'filename' => '<string>',
        'mimeType' => '<string>',
        'sourceSystem' => '<string>',
        'sourceSystemId' => '<string>',
        'type' => '<string>',
        'visibleToCarrier' => true,
        'visibleToCustomer' => true
    ],
    'invoiceId' => '<string>'
  ]),
  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.upwell.com/api/rest/invoices/{invoiceId}/documents"

	payload := strings.NewReader("{\n  \"input\": {\n    \"base64\": \"<string>\",\n    \"filename\": \"<string>\",\n    \"mimeType\": \"<string>\",\n    \"sourceSystem\": \"<string>\",\n    \"sourceSystemId\": \"<string>\",\n    \"type\": \"<string>\",\n    \"visibleToCarrier\": true,\n    \"visibleToCustomer\": true\n  },\n  \"invoiceId\": \"<string>\"\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.upwell.com/api/rest/invoices/{invoiceId}/documents")
  .header("Content-Type", "application/json")
  .body("{\n  \"input\": {\n    \"base64\": \"<string>\",\n    \"filename\": \"<string>\",\n    \"mimeType\": \"<string>\",\n    \"sourceSystem\": \"<string>\",\n    \"sourceSystemId\": \"<string>\",\n    \"type\": \"<string>\",\n    \"visibleToCarrier\": true,\n    \"visibleToCustomer\": true\n  },\n  \"invoiceId\": \"<string>\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.upwell.com/api/rest/invoices/{invoiceId}/documents")

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  \"input\": {\n    \"base64\": \"<string>\",\n    \"filename\": \"<string>\",\n    \"mimeType\": \"<string>\",\n    \"sourceSystem\": \"<string>\",\n    \"sourceSystemId\": \"<string>\",\n    \"type\": \"<string>\",\n    \"visibleToCarrier\": true,\n    \"visibleToCustomer\": true\n  },\n  \"invoiceId\": \"<string>\"\n}"

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

{
  "createInvoiceDocument": {
    "documentId": "<string>",
    "id": "<string>"
  }
}