Accept crypto payments in Django

Step by step

1. 1.Get an API key and a webhook secret

   In the Moonvex dashboard go to “Integration” → “Create key” → type “Secret” (sk_live_…). The key is shown only once: store it on your server as MOONVEX_SECRET_KEY. On the same page add a webhook pointing to an https URL on your server and store its signing secret as MOONVEX_WEBHOOK_SECRET. In Django keep them in settings, read from environment variables. A ProcessedEvent model keyed by event_id protects against double processing.

   # settings.py
   import os
   
   MOONVEX_SECRET_KEY = os.environ["MOONVEX_SECRET_KEY"]  # sk_live_...
   MOONVEX_WEBHOOK_SECRET = os.environ["MOONVEX_WEBHOOK_SECRET"]  # whsec_...
   
   # shop/models.py
   from django.db import models
   
   
   class Order(models.Model):
       class Status(models.TextChoices):
           NEW = "new"
           PAID = "paid"
   
       user = models.ForeignKey("auth.User", on_delete=models.PROTECT)
       total = models.DecimalField(max_digits=18, decimal_places=2)
       status = models.CharField(max_length=16, choices=Status.choices, default=Status.NEW)
       moonvex_payment_id = models.CharField(max_length=64, blank=True)
   
   
   class ProcessedEvent(models.Model):
       # the Moonvex event id is the primary key, so a duplicate is impossible
       event_id = models.CharField(max_length=64, primary_key=True)
       created_at = models.DateTimeField(auto_now_add=True)

2. 2.Create a payment in a view

   The pay view accepts only POST from a signed-in user, creates a payment with str(order.total) as the amount (a DecimalField gives a string like 25.00 with no precision loss) and saves the payment id on the order.

   # shop/views.py
   import requests
   from django.conf import settings
   from django.contrib.auth.decorators import login_required
   from django.shortcuts import get_object_or_404, redirect
   from django.views.decorators.http import require_POST
   
   from .models import Order
   
   
   @login_required
   @require_POST
   def pay(request, order_id: int):
       order = get_object_or_404(Order, pk=order_id, user=request.user, status=Order.Status.NEW)
       r = requests.post(
           "https://api.moonvex.org/v1/payments",
           headers={
               "Authorization": "Bearer " + settings.MOONVEX_SECRET_KEY,
               "Idempotency-Key": f"order-{order.pk}-1",
           },
           json={
               "orderId": str(order.pk),
               "amount": str(order.total),  # Decimal → "25.00", no float
               "currency": "USDT",
               "network": "TRON",
           },
           timeout=15,
       )
       payment = r.json()
       if r.status_code >= 400:
           raise RuntimeError(payment["error"]["code"] + ": " + payment["error"]["message"])
       Order.objects.filter(pk=order.pk).update(moonvex_payment_id=payment["id"])
       return redirect(payment["paymentUrl"])

3. 3.Send the customer to paymentUrl

   paymentUrl is a hosted payment page: the exact amount including the fee, the address, a QR code, the official token contract and a timer, with a status that updates by itself. Open it with a redirect or in a new tab; it cannot be embedded in an iframe. A customer returning to your site is not proof of payment: mark the order paid only from a webhook or the status from GET /v1/payments/:id. In Django: redirect(payment["paymentUrl"]).

4. 4.Receive the webhook and verify the signature

   Moonvex sends a POST with a Moonvex-Signature header: t=<unix time>,v1=<signature>. The signature is a hex HMAC-SHA256 of the string “t.raw_body” keyed with the webhook secret. Compute it over the body bytes before parsing JSON, compare in constant time and reject events older than 5 minutes. For 24 hours after a secret rotation the header carries two v1 values; either one is valid. The webhook view is decorated with @csrf_exempt: Moonvex sends no CSRF token, the signature is the protection. The raw body is request.body.

   # shop/webhooks.py
   import hashlib
   import hmac
   import json
   import time
   
   from django.conf import settings
   from django.http import HttpResponse, HttpResponseBadRequest
   from django.views.decorators.csrf import csrf_exempt
   from django.views.decorators.http import require_POST
   
   from .payments import mark_paid_once
   
   
   def verify_moonvex(raw: bytes, header: str, secret: str, tolerance: int = 300) -> bool:
       parts = [p.split("=", 1) for p in (header or "").split(",") if "=" in p]
       t = next((v for k, v in parts if k == "t"), None)
       if t is None or not t.isdigit() or abs(time.time() - int(t)) > tolerance:
           return False
       expected = hmac.new(secret.encode(), t.encode() + b"." + raw, hashlib.sha256).hexdigest()
       return any(hmac.compare_digest(expected, v) for k, v in parts if k == "v1")
   
   
   @csrf_exempt  # Moonvex has no CSRF token; the HMAC signature is the protection
   @require_POST
   def moonvex_webhook(request):
       raw = request.body  # raw bytes; do not touch request.POST before this
       if not verify_moonvex(raw, request.headers.get("Moonvex-Signature", ""), settings.MOONVEX_WEBHOOK_SECRET):
           return HttpResponseBadRequest("bad signature")
       event = json.loads(raw)
       if event["type"] in ("payment.confirmed", "payment.overpaid"):
           mark_paid_once(event["id"], event["data"]["orderId"])
       return HttpResponse("ok")
   
   
   # urls.py
   # path("orders/<int:order_id>/pay/", views.pay),
   # path("moonvex/webhook/", webhooks.moonvex_webhook),

5. 5.Mark the order paid exactly once

   A redelivered event keeps the same id, so store it in a table with a unique key in the same transaction as the order update: a duplicate then changes nothing. Fulfil on payment.confirmed and payment.overpaid, never on payment.detected. get_or_create inside transaction.atomic: if the row already exists, this is a redelivery and the order is left alone.

   # shop/payments.py
   from django.db import transaction
   
   from .models import Order, ProcessedEvent
   
   
   def mark_paid_once(event_id: str, order_id: str) -> None:
       with transaction.atomic():
           _, created = ProcessedEvent.objects.get_or_create(event_id=event_id)
           if not created:
               return  # a redelivery: do nothing
           Order.objects.filter(pk=int(order_id)).exclude(status=Order.Status.PAID).update(status=Order.Status.PAID)

6. 6.Test the integration

   Moonvex has no test network: everything runs on mainnets. The “Send test” button under “Integration” sends a webhook.test event, which is how you check the signature. Then pay a small invoice, for example 1 USDT on TRON: it is a regular payment and the money lands on your balance. The delivery log with response codes and a “Retry” button is on the same page.

Pitfalls

• Without @csrf_exempt Django answers every webhook with 403, and Moonvex retries a 4xx only 3 times.
• Do not touch request.POST before reading request.body: you do not need it for application/json, and the stream read order matters.
• Send heavy work (emails, granting access) to Celery after responding 200; you have 10 seconds to respond.
• Use DecimalField for prices and str() when sending. A float from FloatField gives amounts like 24.999999.