curl --request PUT \
  --url https://api.loopreturns.com/api/2026-10/inventories/external/{variantExternalId}/{locationExternalId} \
  --header 'Content-Type: application/json' \
  --header 'X-Authorization: <api-key>' \
  --data '
{
  "available_count": 42
}
'

import requests

url = "https://api.loopreturns.com/api/2026-10/inventories/external/{variantExternalId}/{locationExternalId}"

payload = { "available_count": 42 }
headers = {
    "X-Authorization": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'PUT',
  headers: {'X-Authorization': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({available_count: 42})
};

fetch('https://api.loopreturns.com/api/2026-10/inventories/external/{variantExternalId}/{locationExternalId}', 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.loopreturns.com/api/2026-10/inventories/external/{variantExternalId}/{locationExternalId}",
  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([
    'available_count' => 42
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "X-Authorization: <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.loopreturns.com/api/2026-10/inventories/external/{variantExternalId}/{locationExternalId}"

	payload := strings.NewReader("{\n  \"available_count\": 42\n}")

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

	req.Header.Add("X-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.put("https://api.loopreturns.com/api/2026-10/inventories/external/{variantExternalId}/{locationExternalId}")
  .header("X-Authorization", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"available_count\": 42\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.loopreturns.com/api/2026-10/inventories/external/{variantExternalId}/{locationExternalId}")

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

request = Net::HTTP::Put.new(url)
request["X-Authorization"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"available_count\": 42\n}"

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

{
  "inventory": {
    "available_count": 42,
    "product_variant": {
      "id": 674353902539857400,
      "name": "Example Product",
      "external_id": "4006381333931",
      "sku": "EXAMPLEPRODUCT-VAR-1",
      "weight_grams": 444,
      "barcode": 23141001200513
    },
    "location": {
      "id": 680118439701923300,
      "name": "Main Warehouse",
      "status": "active",
      "address": {
        "name": "Main Warehouse",
        "company": "Universal Exports",
        "address1": "1234 Example Street",
        "address2": "Unit 19",
        "city": "Townsville",
        "region": "Louisiana",
        "postal_code": 90210,
        "country_code": "US"
      },
      "external_id": "main-warehouse"
    }
  }
}

{
  "errors": "Unauthorized."
}

{
  "message": "Resource not found."
}

{
  "message": "Multiple product variants match the provided external_id."
}

{
  "message": "The available count field is required.",
  "errors": {
    "available_count": [
      "The available count field is required."
    ]
  }
}