Create a payment

POSThttps://api.testingapis.com/api/PaymentsSign in to see this endpoint's URL

Create a payment. Requires an Idempotency-Key header.

Header: Idempotency-Key: <unique value, e.g. a UUID> (max 255 characters, remembered for 24 hours).

Same key and same body: the original response is replayed with Idempotent-Replayed: true. Bodies are compared after canonicalizing, so key order and whitespace don't matter. Same key and a different body: 422. Same key while the first request is still processing: 409. A request that fails validation isn't remembered, so its key can be reused. Test data: cardLast4 0002 is always declined (status failed, still 201). bank_transfer payments start as pending.

Note: Retrying with the same Idempotency-Key and body replays the stored response (Idempotent-Replayed: true). A card ending 0002 is always declined.

Parameters 2

Name	Type	Description
`processingSeconds`	query · integer (int32)	Hold the request open for this many seconds (max 5) so a duplicate can be sent while it is in flight. Default: 0.
`Idempotency-Key`required	header · string	Unique key per logical payment. Same key + same body replays the stored response; a different body returns 422.

Request body

Optional. application/json, text/json, application/*+json, application/xml, text/xml, application/*+xml. userId, orderId (optional), amount (greater than 0, max 1,000,000), currency (3-letter code), method (card, upi, paypal or bank_transfer), description, cardLast4 (4 digits, required for card).

Example body

{
  "userId": 101,
  "amount": 49.99,
  "currency": "usd",
  "method": "card",
  "cardLast4": "4242",
  "description": "Order #1001"
}

Responses

200: OK
201: Payment created, or the original response replayed.
400: Idempotency-Key missing or too long, or the body is invalid.
409: A request with the same key is still being processed.
422: The key was already used with a different body.

Example

Request

curl -X POST "https://api.testingapis.com/api/Payments" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: {{uuid}}" \
  -d '{"userId": 101, "amount": 49.99, "currency": "usd", "method": "card", "cardLast4": "4242", "description": "Order #1001"}' \
  -H "X-TestingApis-Key: YOUR_API_KEY"

Response201 Created

{
  "message": "Payment created successfully",
  "idempotencyKey": "cda26651-04d6-4941-8323-2fcaffd05efa",
  "data": {
    "id": 14,
    "userId": 101,
    "orderId": null,
    "amount": 49.99,
    "currency": "USD",
    "method": "card",
    "status": "succeeded",
    "description": "Order #1001",
    "cardLast4": "4242",
    "createdAt": "2026-09-30T18:26:45Z",
… (3 more lines)

The parameters, request and response examples and the live Try it panel for this endpoint are for signed-in members. Accounts are free and take a few seconds to create.

curl -X POST 'https://api.testingapis.com/api/Payments' \ -H 'Idempotency-Key: {{uuid}}' \ -H 'Content-Type: application/json' \ -H 'X-TestingApis-Key: YOUR_API_KEY' \ -d '{"userId": 101, "amount": 49.99, "currency": "usd", "method": "card", "cardLast4": "4242", "description": "Order #1001"}'

const res = await fetch("https://api.testingapis.com/api/Payments", { method: "POST", headers: { "Idempotency-Key": "{{uuid}}", "Content-Type": "application/json", "X-TestingApis-Key": "YOUR_API_KEY", }, body: "{\"userId\": 101, \"amount\": 49.99, \"currency\": \"usd\", \"method\": \"card\", \"cardLast4\": \"4242\", \"description\": \"Order #1001\"}", }); console.log(res.status, await res.text());

import requests res = requests.post( "https://api.testingapis.com/api/Payments", headers={ "Idempotency-Key": "{{uuid}}", "Content-Type": "application/json", "X-TestingApis-Key": "YOUR_API_KEY", }, data="{\"userId\": 101, \"amount\": 49.99, \"currency\": \"usd\", \"method\": \"card\", \"cardLast4\": \"4242\", \"description\": \"Order #1001\"}", ) print(res.status_code, res.text)

using System.Net.Http.Headers; using var client = new HttpClient(); using var request = new HttpRequestMessage(HttpMethod.Post, "https://api.testingapis.com/api/Payments"); request.Headers.TryAddWithoutValidation("Idempotency-Key", "{{uuid}}"); request.Headers.TryAddWithoutValidation("X-TestingApis-Key", "YOUR_API_KEY"); request.Content = new StringContent("{\"userId\": 101, \"amount\": 49.99, \"currency\": \"usd\", \"method\": \"card\", \"cardLast4\": \"4242\", \"description\": \"Order #1001\"}"); request.Content.Headers.ContentType = MediaTypeHeaderValue.Parse("application/json"); using var response = await client.SendAsync(request); Console.WriteLine($"{(int)response.StatusCode} {await response.Content.ReadAsStringAsync()}");

import java.net.URI; import java.net.http.HttpClient; import java.net.http.HttpRequest; import java.net.http.HttpResponse; public class Main { public static void main(String[] args) throws Exception { HttpClient client = HttpClient.newHttpClient(); HttpRequest request = HttpRequest.newBuilder(URI.create("https://api.testingapis.com/api/Payments")) .header("Idempotency-Key", "{{uuid}}") .header("X-TestingApis-Key", "YOUR_API_KEY") .header("Content-Type", "application/json") .method("POST", HttpRequest.BodyPublishers.ofString("{\"userId\": 101, \"amount\": 49.99, \"currency\": \"usd\", \"method\": \"card\", \"cardLast4\": \"4242\", \"description\": \"Order #1001\"}")) .build(); HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString()); System.out.println(response.statusCode() + " " + response.body()); } }

package main import ( "fmt" "io" "net/http" "strings" ) func main() { body := strings.NewReader("{\"userId\": 101, \"amount\": 49.99, \"currency\": \"usd\", \"method\": \"card\", \"cardLast4\": \"4242\", \"description\": \"Order #1001\"}") req, err := http.NewRequest("POST", "https://api.testingapis.com/api/Payments", body) if err != nil { panic(err) } req.Header.Set("Idempotency-Key", "{{uuid}}") req.Header.Set("X-TestingApis-Key", "YOUR_API_KEY") req.Header.Set("Content-Type", "application/json") res, err := http.DefaultClient.Do(req) if err != nil { panic(err) } defer res.Body.Close() data, err := io.ReadAll(res.Body) if err != nil { panic(err) } fmt.Println(res.StatusCode, string(data)) }