curl --request PATCH \
  --url https://api.wellapp.ai/v1/invoice-items/{id} \
  --header 'Authorization: <authorization>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "type": "invoice_item",
  "attributes": {
    "line_id": "1",
    "sku": "WM-1001",
    "name": "Wireless Mouse",
    "description": "Ergonomic wireless mouse with USB receiver",
    "unit_price": 25,
    "currency": "EUR",
    "unit": "EA",
    "min_quantity": 1,
    "max_quantity": 500,
    "tax": {
      "rate": 20,
      "category": "standard",
      "scheme": "VAT"
    },
    "period": {
      "start": "2025-06-26",
      "end": "2025-06-27"
    }
  },
  "relationships": {
    "invoices": {
      "data": [
        {
          "type": "invoice",
          "id": "invoice1"
        }
      ]
    }
  }
}
'

import requests

url = "https://api.wellapp.ai/v1/invoice-items/{id}"

payload = {
    "type": "invoice_item",
    "attributes": {
        "line_id": "1",
        "sku": "WM-1001",
        "name": "Wireless Mouse",
        "description": "Ergonomic wireless mouse with USB receiver",
        "unit_price": 25,
        "currency": "EUR",
        "unit": "EA",
        "min_quantity": 1,
        "max_quantity": 500,
        "tax": {
            "rate": 20,
            "category": "standard",
            "scheme": "VAT"
        },
        "period": {
            "start": "2025-06-26",
            "end": "2025-06-27"
        }
    },
    "relationships": { "invoices": { "data": [
                {
                    "type": "invoice",
                    "id": "invoice1"
                }
            ] } }
}
headers = {
    "Authorization": "<authorization>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'PATCH',
  headers: {Authorization: '<authorization>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    type: 'invoice_item',
    attributes: {
      line_id: '1',
      sku: 'WM-1001',
      name: 'Wireless Mouse',
      description: 'Ergonomic wireless mouse with USB receiver',
      unit_price: 25,
      currency: 'EUR',
      unit: 'EA',
      min_quantity: 1,
      max_quantity: 500,
      tax: {rate: 20, category: 'standard', scheme: 'VAT'},
      period: {start: '2025-06-26', end: '2025-06-27'}
    },
    relationships: {invoices: {data: [{type: 'invoice', id: 'invoice1'}]}}
  })
};

fetch('https://api.wellapp.ai/v1/invoice-items/{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.wellapp.ai/v1/invoice-items/{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([
    'type' => 'invoice_item',
    'attributes' => [
        'line_id' => '1',
        'sku' => 'WM-1001',
        'name' => 'Wireless Mouse',
        'description' => 'Ergonomic wireless mouse with USB receiver',
        'unit_price' => 25,
        'currency' => 'EUR',
        'unit' => 'EA',
        'min_quantity' => 1,
        'max_quantity' => 500,
        'tax' => [
                'rate' => 20,
                'category' => 'standard',
                'scheme' => 'VAT'
        ],
        'period' => [
                'start' => '2025-06-26',
                'end' => '2025-06-27'
        ]
    ],
    'relationships' => [
        'invoices' => [
                'data' => [
                                [
                                                                'type' => 'invoice',
                                                                'id' => 'invoice1'
                                ]
                ]
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: <authorization>",
    "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.wellapp.ai/v1/invoice-items/{id}"

	payload := strings.NewReader("{\n  \"type\": \"invoice_item\",\n  \"attributes\": {\n    \"line_id\": \"1\",\n    \"sku\": \"WM-1001\",\n    \"name\": \"Wireless Mouse\",\n    \"description\": \"Ergonomic wireless mouse with USB receiver\",\n    \"unit_price\": 25,\n    \"currency\": \"EUR\",\n    \"unit\": \"EA\",\n    \"min_quantity\": 1,\n    \"max_quantity\": 500,\n    \"tax\": {\n      \"rate\": 20,\n      \"category\": \"standard\",\n      \"scheme\": \"VAT\"\n    },\n    \"period\": {\n      \"start\": \"2025-06-26\",\n      \"end\": \"2025-06-27\"\n    }\n  },\n  \"relationships\": {\n    \"invoices\": {\n      \"data\": [\n        {\n          \"type\": \"invoice\",\n          \"id\": \"invoice1\"\n        }\n      ]\n    }\n  }\n}")

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

	req.Header.Add("Authorization", "<authorization>")
	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.wellapp.ai/v1/invoice-items/{id}")
  .header("Authorization", "<authorization>")
  .header("Content-Type", "application/json")
  .body("{\n  \"type\": \"invoice_item\",\n  \"attributes\": {\n    \"line_id\": \"1\",\n    \"sku\": \"WM-1001\",\n    \"name\": \"Wireless Mouse\",\n    \"description\": \"Ergonomic wireless mouse with USB receiver\",\n    \"unit_price\": 25,\n    \"currency\": \"EUR\",\n    \"unit\": \"EA\",\n    \"min_quantity\": 1,\n    \"max_quantity\": 500,\n    \"tax\": {\n      \"rate\": 20,\n      \"category\": \"standard\",\n      \"scheme\": \"VAT\"\n    },\n    \"period\": {\n      \"start\": \"2025-06-26\",\n      \"end\": \"2025-06-27\"\n    }\n  },\n  \"relationships\": {\n    \"invoices\": {\n      \"data\": [\n        {\n          \"type\": \"invoice\",\n          \"id\": \"invoice1\"\n        }\n      ]\n    }\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.wellapp.ai/v1/invoice-items/{id}")

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

request = Net::HTTP::Patch.new(url)
request["Authorization"] = '<authorization>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"type\": \"invoice_item\",\n  \"attributes\": {\n    \"line_id\": \"1\",\n    \"sku\": \"WM-1001\",\n    \"name\": \"Wireless Mouse\",\n    \"description\": \"Ergonomic wireless mouse with USB receiver\",\n    \"unit_price\": 25,\n    \"currency\": \"EUR\",\n    \"unit\": \"EA\",\n    \"min_quantity\": 1,\n    \"max_quantity\": 500,\n    \"tax\": {\n      \"rate\": 20,\n      \"category\": \"standard\",\n      \"scheme\": \"VAT\"\n    },\n    \"period\": {\n      \"start\": \"2025-06-26\",\n      \"end\": \"2025-06-27\"\n    }\n  },\n  \"relationships\": {\n    \"invoices\": {\n      \"data\": [\n        {\n          \"type\": \"invoice\",\n          \"id\": \"invoice1\"\n        }\n      ]\n    }\n  }\n}"

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

{
  "data": {
    "type": "invoice_item",
    "id": "item_001",
    "attributes": {
      "line_id": "1",
      "sku": "WM-1001",
      "name": "Wireless Mouse",
      "description": "Ergonomic wireless mouse with USB receiver",
      "unit_price": 25,
      "currency": "EUR",
      "unit": "EA",
      "min_quantity": 1,
      "max_quantity": 500,
      "tax": {
        "rate": 20,
        "category": "standard",
        "scheme": "VAT"
      },
      "period": {
        "start": "2025-06-26",
        "end": "2025-06-27"
      },
      "created_at": "2025-05-11T13:42:12Z",
      "updated_at": "2025-05-11T13:45:20Z"
    },
    "relationships": {
      "invoices": {
        "data": [
          {
            "type": "invoice",
            "id": "invoice1"
          }
        ]
      },
      "medias": {
        "data": [
          {
            "type": "media",
            "id": "media-1"
          }
        ]
      }
    }
  },
  "included": [
    {
      "type": "invoice",
      "id": "invoice1",
      "attributes": {
        "reference_number": "INV-2025-001",
        "document_type": "commercial_invoice",
        "document_type_code": "380",
        "issue_date": "2025-01-15",
        "due_date": "2025-02-15",
        "local_currency": "EUR",
        "local_totals": {
          "subtotal": "1000.00",
          "tax_total": "200.00",
          "total_amount": "1200.00"
        },
        "terms": "Payment due within 30 days",
        "billing_context": "subscription",
        "payment_status": {
          "paid": false,
          "amount_paid": 0,
          "amount_remaining": 1200
        },
        "status": "draft",
        "description": "Professional services invoice for January 2025",
        "created_at": "2025-01-15T10:30:00Z",
        "updated_at": "2025-01-15T10:30:00Z"
      }
    },
    {
      "type": "media",
      "id": "media-1",
      "attributes": {
        "media_type": "logo",
        "is_primary": true,
        "url": "https://cdn.example.com/product-images/wireless-mouse.jpg",
        "created_at": "2025-05-11T13:00:00Z",
        "updated_at": "2025-05-11T13:00:00Z"
      }
    }
  ]
}

{
  "code": "SCHEMA_VALIDATION_ERROR",
  "status": 400,
  "title": "Validation Error",
  "message": "The request is invalid",
  "meta": {
    "log_id": "65c669d4-679c-4a8b-b8c0-fbe37699bb5b"
  },
  "details": [
    {
      "instancePath": "<string>",
      "schemaPath": "<string>",
      "keyword": "<string>",
      "params": {},
      "message": "<string>"
    }
  ]
}

{
  "code": "UNAUTHORIZED",
  "status": 401,
  "title": "Unauthorized",
  "message": "You are not authorized to access this resource",
  "meta": {
    "log_id": "65c669d4-679c-4a8b-b8c0-fbe37699bb5b"
  }
}