curl --request POST \
  --url https://{site}/wp-json/joinery/v1/rules \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "name": "Bulk hardware",
  "active": true,
  "priority": 10,
  "exclusive": false,
  "conditions": [
    {
      "type": "product_category",
      "settings": {
        "categories": [
          17
        ]
      }
    }
  ],
  "actions": [
    {
      "type": "dp_tiered_price",
      "settings": {
        "tiers": [
          {
            "min": 10,
            "percent": 10
          },
          {
            "min": 50,
            "percent": 20
          }
        ]
      }
    }
  ]
}
'

import requests

url = "https://{site}/wp-json/joinery/v1/rules"

payload = {
    "name": "Bulk hardware",
    "active": True,
    "priority": 10,
    "exclusive": False,
    "conditions": [
        {
            "type": "product_category",
            "settings": { "categories": [17] }
        }
    ],
    "actions": [
        {
            "type": "dp_tiered_price",
            "settings": { "tiers": [
                    {
                        "min": 10,
                        "percent": 10
                    },
                    {
                        "min": 50,
                        "percent": 20
                    }
                ] }
        }
    ]
}
headers = {
    "Authorization": "Basic <encoded-value>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Basic <encoded-value>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    name: 'Bulk hardware',
    active: true,
    priority: 10,
    exclusive: false,
    conditions: [{type: 'product_category', settings: {categories: [17]}}],
    actions: [
      {
        type: 'dp_tiered_price',
        settings: {tiers: [{min: 10, percent: 10}, {min: 50, percent: 20}]}
      }
    ]
  })
};

fetch('https://{site}/wp-json/joinery/v1/rules', 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://{site}/wp-json/joinery/v1/rules",
  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' => 'Bulk hardware',
    'active' => true,
    'priority' => 10,
    'exclusive' => false,
    'conditions' => [
        [
                'type' => 'product_category',
                'settings' => [
                                'categories' => [
                                                                17
                                ]
                ]
        ]
    ],
    'actions' => [
        [
                'type' => 'dp_tiered_price',
                'settings' => [
                                'tiers' => [
                                                                [
                                                                                                                                'min' => 10,
                                                                                                                                'percent' => 10
                                                                ],
                                                                [
                                                                                                                                'min' => 50,
                                                                                                                                'percent' => 20
                                                                ]
                                ]
                ]
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Basic <encoded-value>",
    "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://{site}/wp-json/joinery/v1/rules"

	payload := strings.NewReader("{\n  \"name\": \"Bulk hardware\",\n  \"active\": true,\n  \"priority\": 10,\n  \"exclusive\": false,\n  \"conditions\": [\n    {\n      \"type\": \"product_category\",\n      \"settings\": {\n        \"categories\": [\n          17\n        ]\n      }\n    }\n  ],\n  \"actions\": [\n    {\n      \"type\": \"dp_tiered_price\",\n      \"settings\": {\n        \"tiers\": [\n          {\n            \"min\": 10,\n            \"percent\": 10\n          },\n          {\n            \"min\": 50,\n            \"percent\": 20\n          }\n        ]\n      }\n    }\n  ]\n}")

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

	req.Header.Add("Authorization", "Basic <encoded-value>")
	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://{site}/wp-json/joinery/v1/rules")
  .header("Authorization", "Basic <encoded-value>")
  .header("Content-Type", "application/json")
  .body("{\n  \"name\": \"Bulk hardware\",\n  \"active\": true,\n  \"priority\": 10,\n  \"exclusive\": false,\n  \"conditions\": [\n    {\n      \"type\": \"product_category\",\n      \"settings\": {\n        \"categories\": [\n          17\n        ]\n      }\n    }\n  ],\n  \"actions\": [\n    {\n      \"type\": \"dp_tiered_price\",\n      \"settings\": {\n        \"tiers\": [\n          {\n            \"min\": 10,\n            \"percent\": 10\n          },\n          {\n            \"min\": 50,\n            \"percent\": 20\n          }\n        ]\n      }\n    }\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://{site}/wp-json/joinery/v1/rules")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Basic <encoded-value>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"name\": \"Bulk hardware\",\n  \"active\": true,\n  \"priority\": 10,\n  \"exclusive\": false,\n  \"conditions\": [\n    {\n      \"type\": \"product_category\",\n      \"settings\": {\n        \"categories\": [\n          17\n        ]\n      }\n    }\n  ],\n  \"actions\": [\n    {\n      \"type\": \"dp_tiered_price\",\n      \"settings\": {\n        \"tiers\": [\n          {\n            \"min\": 10,\n            \"percent\": 10\n          },\n          {\n            \"min\": 50,\n            \"percent\": 20\n          }\n        ]\n      }\n    }\n  ]\n}"

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

{
  "id": 1,
  "name": "Bulk hardware",
  "active": true,
  "priority": 10,
  "exclusive": false,
  "conditions": [
    {
      "type": "product_category",
      "settings": {
        "categories": [
          17
        ]
      }
    }
  ],
  "actions": [
    {
      "type": "dp_tiered_price",
      "settings": {
        "tiers": [
          {
            "min": 10,
            "percent": 10
          },
          {
            "min": 50,
            "percent": 20
          }
        ]
      }
    }
  ]
}

{
  "code": "<string>",
  "message": "<string>",
  "data": {
    "status": 123
  }
}

{
  "code": "<string>",
  "message": "<string>",
  "data": {
    "status": 123
  }
}

{
  "code": "<string>",
  "message": "<string>",
  "data": {
    "status": 123
  }
}