curl --request POST \
  --url https://api.revtain.com/api/cancel-flow/generate \
  --header 'Content-Type: application/json' \
  --header 'X-API-KEY: <api-key>' \
  --data '
{
  "customerId": "cus_abc123",
  "customerEmail": "customer@example.com",
  "subscriptionId": "sub_789",
  "amount": 2900,
  "currency": "USD",
  "returnUrl": "https://app.yourdomain.com/account"
}
'

import requests

url = "https://api.revtain.com/api/cancel-flow/generate"

payload = {
    "customerId": "cus_abc123",
    "customerEmail": "customer@example.com",
    "subscriptionId": "sub_789",
    "amount": 2900,
    "currency": "USD",
    "returnUrl": "https://app.yourdomain.com/account"
}
headers = {
    "X-API-KEY": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'X-API-KEY': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    customerId: 'cus_abc123',
    customerEmail: 'customer@example.com',
    subscriptionId: 'sub_789',
    amount: 2900,
    currency: 'USD',
    returnUrl: 'https://app.yourdomain.com/account'
  })
};

fetch('https://api.revtain.com/api/cancel-flow/generate', 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.revtain.com/api/cancel-flow/generate",
  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([
    'customerId' => 'cus_abc123',
    'customerEmail' => 'customer@example.com',
    'subscriptionId' => 'sub_789',
    'amount' => 2900,
    'currency' => 'USD',
    'returnUrl' => 'https://app.yourdomain.com/account'
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "X-API-KEY: <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.revtain.com/api/cancel-flow/generate"

	payload := strings.NewReader("{\n  \"customerId\": \"cus_abc123\",\n  \"customerEmail\": \"customer@example.com\",\n  \"subscriptionId\": \"sub_789\",\n  \"amount\": 2900,\n  \"currency\": \"USD\",\n  \"returnUrl\": \"https://app.yourdomain.com/account\"\n}")

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

	req.Header.Add("X-API-KEY", "<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.revtain.com/api/cancel-flow/generate")
  .header("X-API-KEY", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"customerId\": \"cus_abc123\",\n  \"customerEmail\": \"customer@example.com\",\n  \"subscriptionId\": \"sub_789\",\n  \"amount\": 2900,\n  \"currency\": \"USD\",\n  \"returnUrl\": \"https://app.yourdomain.com/account\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.revtain.com/api/cancel-flow/generate")

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

request = Net::HTTP::Post.new(url)
request["X-API-KEY"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"customerId\": \"cus_abc123\",\n  \"customerEmail\": \"customer@example.com\",\n  \"subscriptionId\": \"sub_789\",\n  \"amount\": 2900,\n  \"currency\": \"USD\",\n  \"returnUrl\": \"https://app.yourdomain.com/account\"\n}"

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

{
  "url": "https://api.revtain.com/api/cancel-flow/abc123xyz...",
  "token": "abc123xyz...",
  "expiresAt": "2026-05-23T14:30:00.000Z"
}

{
  "error": "Validation failed.",
  "details": {
    "paymentMethodToken": [
      "Payment method token is required"
    ],
    "amount": [
      "Amount must be a positive number"
    ]
  }
}

{
  "error": "Unauthorized. Missing or invalid API key."
}

{
  "error": "Cancel flow is not enabled for this account.",
  "message": "Contact Revtain to enable the hosted cancel flow for your account."
}