curl --request POST \
  --url https://api.rivermarkets.com/v1/watchlists \
  --header 'Content-Type: application/json' \
  --header 'X-River-Key-Id: <api-key>' \
  --header 'X-River-Signature: <api-key>' \
  --header 'X-River-Timestamp: <api-key>' \
  --data '
{
  "subaccount_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "name": "<string>",
  "description": "<string>",
  "river_ids": [
    123
  ]
}
'

import requests

url = "https://api.rivermarkets.com/v1/watchlists"

payload = {
    "subaccount_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "name": "<string>",
    "description": "<string>",
    "river_ids": [123]
}
headers = {
    "X-River-Key-Id": "<api-key>",
    "X-River-Timestamp": "<api-key>",
    "X-River-Signature": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {
    'X-River-Key-Id': '<api-key>',
    'X-River-Timestamp': '<api-key>',
    'X-River-Signature': '<api-key>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    subaccount_id: '3c90c3cc-0d44-4b50-8888-8dd25736052a',
    name: '<string>',
    description: '<string>',
    river_ids: [123]
  })
};

fetch('https://api.rivermarkets.com/v1/watchlists', 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.rivermarkets.com/v1/watchlists",
  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([
    'subaccount_id' => '3c90c3cc-0d44-4b50-8888-8dd25736052a',
    'name' => '<string>',
    'description' => '<string>',
    'river_ids' => [
        123
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "X-River-Key-Id: <api-key>",
    "X-River-Signature: <api-key>",
    "X-River-Timestamp: <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.rivermarkets.com/v1/watchlists"

	payload := strings.NewReader("{\n  \"subaccount_id\": \"3c90c3cc-0d44-4b50-8888-8dd25736052a\",\n  \"name\": \"<string>\",\n  \"description\": \"<string>\",\n  \"river_ids\": [\n    123\n  ]\n}")

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

	req.Header.Add("X-River-Key-Id", "<api-key>")
	req.Header.Add("X-River-Timestamp", "<api-key>")
	req.Header.Add("X-River-Signature", "<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.post("https://api.rivermarkets.com/v1/watchlists")
  .header("X-River-Key-Id", "<api-key>")
  .header("X-River-Timestamp", "<api-key>")
  .header("X-River-Signature", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"subaccount_id\": \"3c90c3cc-0d44-4b50-8888-8dd25736052a\",\n  \"name\": \"<string>\",\n  \"description\": \"<string>\",\n  \"river_ids\": [\n    123\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.rivermarkets.com/v1/watchlists")

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

request = Net::HTTP::Post.new(url)
request["X-River-Key-Id"] = '<api-key>'
request["X-River-Timestamp"] = '<api-key>'
request["X-River-Signature"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"subaccount_id\": \"3c90c3cc-0d44-4b50-8888-8dd25736052a\",\n  \"name\": \"<string>\",\n  \"description\": \"<string>\",\n  \"river_ids\": [\n    123\n  ]\n}"

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

{
  "watchlist_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "owner_subaccount_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "name": "<string>",
  "river_ids": [
    123
  ],
  "members": [
    {
      "river_id": 123,
      "exchange_value": 123,
      "exchange_name": "<string>",
      "tick_size_price": 123,
      "tick_size_qty": 123,
      "minimum_order_size": 123,
      "neg_risk": true,
      "name": "<string>",
      "ticker": "<string>",
      "token_id_yes": "<string>",
      "token_id_no": "<string>",
      "slug": "<string>",
      "tick_structure": "uniform",
      "expiration_datetime": "<string>",
      "start_datetime": "<string>",
      "neg_risk_id": "<string>",
      "condition_id": "<string>",
      "subtitle": "<string>",
      "description": "<string>",
      "category": "Other",
      "subcategory": "<string>",
      "rank": 123,
      "event_ticker": "<string>",
      "event_title": "<string>",
      "volume": 123,
      "volume_24h": 123,
      "series_ticker": "<string>",
      "image": "<string>",
      "last_price": 123,
      "primary_entity_name": "<string>"
    }
  ],
  "created_at": "<string>",
  "description": "<string>"
}

{
  "detail": [
    {
      "loc": [
        "<string>"
      ],
      "msg": "<string>",
      "type": "<string>",
      "input": "<unknown>",
      "ctx": {}
    }
  ]
}