curl --request PATCH \
  --url https://api.fintoc.com/v2/invoices/{id} \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "metadata": {
    "order_id": "1234"
  }
}
'

import requests

url = "https://api.fintoc.com/v2/invoices/{id}"

payload = { "metadata": { "order_id": "1234" } }
headers = {
    "Authorization": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'PATCH',
  headers: {Authorization: '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({metadata: {order_id: '1234'}})
};

fetch('https://api.fintoc.com/v2/invoices/{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.fintoc.com/v2/invoices/{id}",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "PATCH",
  CURLOPT_POSTFIELDS => json_encode([
    'metadata' => [
        'order_id' => '1234'
    ]
  ]),
  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://api.fintoc.com/v2/invoices/{id}"

	payload := strings.NewReader("{\n  \"metadata\": {\n    \"order_id\": \"1234\"\n  }\n}")

	req, _ := http.NewRequest("PATCH", 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.patch("https://api.fintoc.com/v2/invoices/{id}")
  .header("Authorization", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"metadata\": {\n    \"order_id\": \"1234\"\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.fintoc.com/v2/invoices/{id}")

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

request = Net::HTTP::Patch.new(url)
request["Authorization"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"metadata\": {\n    \"order_id\": \"1234\"\n  }\n}"

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

{
  "id": "inv_2bVdWxLpzXq8RkNcM3JtUv9AhTe",
  "object": "invoice",
  "attempt_count": 0,
  "collection_method": "charge_automatically",
  "created_at": "2026-05-01T12:00:00Z",
  "currency": "CLP",
  "customer": "cus_2bVdWyTnGq4PfLs7DkXjRm0CwIo",
  "default_payment_method": "pm_2bVdX3StMv9UkQxCIpCoWr5H1Nt",
  "hosted_invoice_url": "https://acme.billing.fintoc.com/invoices/inv_2bVdWxLpzXq8RkNcM3JtUv9AhTe",
  "lines": [
    {
      "id": "il_2bVdX0PqJs6RhNu9FmZlTo2EyKq",
      "object": "line_item",
      "name": "Premium Plan",
      "description": "A premium plan",
      "amount": 30000,
      "currency": "CLP",
      "period_end": "2026-06-01T00:00:00Z",
      "period_start": "2026-05-01T00:00:00Z",
      "quantity": 1
    }
  ],
  "metadata": {
    "order_id": "1234"
  },
  "mode": "live",
  "next_payment_attempt_at": null,
  "payments": [],
  "status": "open",
  "subscription": "sub_2bVdWzKfHr5QgMt8ElYkSn1DxJp",
  "total": 30000
}

{
  "error": {
    "type": "invalid_request_error",
    "code": "invalid_metadata",
    "param": "metadata",
    "message": "Array values not permitted in Metadata",
    "doc_url": "https://docs.fintoc.com/reference/errors"
  }
}

{
  "error": {
    "type": "authentication_error",
    "code": "invalid_api_key",
    "message": "Invalid API Key: invalid-*oken"
  }
}

{
  "error": {
    "type": "invalid_request_error",
    "code": "missing_resource",
    "param": "id",
    "message": "No such invoice: inv_fake_id",
    "doc_url": "https://docs.fintoc.com/reference/errors"
  }
}