curl --request POST \
  --url http://localhost:4000/v1/billing/complete \
  --header 'Content-Type: application/json' \
  --data '
{
  "checkoutId": "<string>"
}
'

const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({checkoutId: '<string>'})
};

fetch('http://localhost:4000/v1/billing/complete', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

import requests

url = "http://localhost:4000/v1/billing/complete"

payload = { "checkoutId": "<string>" }
headers = {"Content-Type": "application/json"}

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

print(response.text)

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "http://localhost:4000/v1/billing/complete"

	payload := strings.NewReader("{\n  \"checkoutId\": \"<string>\"\n}")

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

	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))

}

{}