Apply an order-level adjustment (discount, fee, or coupon)

Applies an order-level adjustment — a discount, fee, or coupon — to an existing order. The adjustment is recorded in order_adjustments and the order totals are recalculated immediately. Adjustments can be added to orders in draft or open status; terminal orders (cancelled, fulfilled, posted-invoice) reject with 422.

Supported effect_type values: discount, fee. Supported discount_type values: percentage, fixed_amount.

To apply a coupon by code instead, use POST /v1/orders/{id}/apply-coupon.

Idempotent via Idempotency-Key header. Requires orders:write scope.

Layer 1 isolation: entity_id is resolved server-side from your API key and the order’s ownership is pre-flight verified before any mutation. Callers do not pass entity_id in the body; any supplied value is ignored in favor of the key-resolved value. Cross-tenant attempts (POSTing a foreign order UUID) return HTTP 404 order_not_found.

POST /orders/{id}/adjustments

Apply an order-level adjustment (discount, fee, or coupon)

cURL

curl --request POST \
  --url https://api.arcuserp.com/v1/orders/{id}/adjustments \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "name": "Summer Promo 10%",
  "effect_type": "discount",
  "discount_type": "percentage",
  "value": 10,
  "notes": "Applied via API integration - summer campaign"
}
'

import requests

url = "https://api.arcuserp.com/v1/orders/{id}/adjustments"

payload = {
    "name": "Summer Promo 10%",
    "effect_type": "discount",
    "discount_type": "percentage",
    "value": 10,
    "notes": "Applied via API integration - summer campaign"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    name: 'Summer Promo 10%',
    effect_type: 'discount',
    discount_type: 'percentage',
    value: 10,
    notes: 'Applied via API integration - summer campaign'
  })
};

fetch('https://api.arcuserp.com/v1/orders/{id}/adjustments', 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.arcuserp.com/v1/orders/{id}/adjustments",
  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([
    'name' => 'Summer Promo 10%',
    'effect_type' => 'discount',
    'discount_type' => 'percentage',
    'value' => 10,
    'notes' => 'Applied via API integration - summer campaign'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "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.arcuserp.com/v1/orders/{id}/adjustments"

	payload := strings.NewReader("{\n  \"name\": \"Summer Promo 10%\",\n  \"effect_type\": \"discount\",\n  \"discount_type\": \"percentage\",\n  \"value\": 10,\n  \"notes\": \"Applied via API integration - summer campaign\"\n}")

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

	req.Header.Add("Authorization", "Bearer <token>")
	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.arcuserp.com/v1/orders/{id}/adjustments")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"name\": \"Summer Promo 10%\",\n  \"effect_type\": \"discount\",\n  \"discount_type\": \"percentage\",\n  \"value\": 10,\n  \"notes\": \"Applied via API integration - summer campaign\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.arcuserp.com/v1/orders/{id}/adjustments")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"name\": \"Summer Promo 10%\",\n  \"effect_type\": \"discount\",\n  \"discount_type\": \"percentage\",\n  \"value\": 10,\n  \"notes\": \"Applied via API integration - summer campaign\"\n}"

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

200

{}

{
  "error": "not_found",
  "code": "not_found",
  "type": "not_found",
  "hint": "The requested order does not exist or does not belong to this entity.",
  "param": "expand[0]",
  "required": "accounts:read",
  "request_id": "req_abc123"
}

{
  "error": "not_found",
  "code": "not_found",
  "type": "not_found",
  "hint": "The requested order does not exist or does not belong to this entity.",
  "param": "expand[0]",
  "required": "accounts:read",
  "request_id": "req_abc123"
}

{
  "error": "not_found",
  "code": "not_found",
  "type": "not_found",
  "hint": "The requested order does not exist or does not belong to this entity.",
  "param": "expand[0]",
  "required": "accounts:read",
  "request_id": "req_abc123"
}

{
  "error": "not_found",
  "code": "not_found",
  "type": "not_found",
  "hint": "The requested order does not exist or does not belong to this entity.",
  "param": "expand[0]",
  "required": "accounts:read",
  "request_id": "req_abc123"
}

{
  "error": "not_found",
  "code": "not_found",
  "type": "not_found",
  "hint": "The requested order does not exist or does not belong to this entity.",
  "param": "expand[0]",
  "required": "accounts:read",
  "request_id": "req_abc123"
}

Authorizations

Authorization · string · header · required

API key issued per entity via Settings > Developers > API Keys. Each key carries scopes (e.g. orders:read, products:write). Bearer token format: Authorization: Bearer ark_live_ent_Test keys use ark_test_ent_. Both are issued per entity
via Settings > Developers > API Keys.

Headers

Idempotency-Key · string

Client-generated unique key for idempotent POST/PATCH/DELETE operations. Alias for the Idempotency parameter. Max 255 chars. On retry with the same key, the original response is returned without re-executing the operation. Keys expire after 24 hours.

Maximum string length: 255

Path Parameters

id · string<uuid> · required

UUID of the order to apply the adjustment to.

Body

application/json

name · string · required

Display label for the adjustment (e.g. "Summer Promo 10%", "Rush Fee").

effect_type · enum<string> · required

Whether this adjustment reduces (discount) or increases (fee) the order total.

Available options: discount, fee

discount_type · enum<string> · required

How value is interpreted.

Available options: percentage, fixed_amount

value · number · required

Numeric value. For percentage, 0--100. For fixed_amount, a dollar amount.

coupon_id · string<uuid>

Optional. If provided, applies the named coupon instead of a manual adjustment.

notes · string

Optional internal notes.

applied_by · string<uuid>

UUID of the user applying the adjustment. Defaults to API key owner if omitted.

Response

200

application/json

Adjustment applied and order totals recalculated.

The created adjustment row with updated order total.