pip install deckle

# settings.py
DECKLE_API_KEY = os.environ.get("DECKLE_API_KEY")

# views.py
import json
from django.conf import settings
from django.http import JsonResponse, HttpResponse
from django.views.decorators.csrf import csrf_exempt
from deckle import Deckle

df = Deckle(settings.DECKLE_API_KEY)


@csrf_exempt
def generate_pdf(request):
    if request.method != "POST":
        return JsonResponse({"error": "Method not allowed"}, status=405)

    body = json.loads(request.body)
    pdf = df.generate(
        html=body["html"],
        options=body.get("options", {"format": "A4"}),
    )
    return JsonResponse({
        "id": pdf.id,
        "url": pdf.url,
        "pages": pdf.pages,
    })


def download_invoice(request, invoice_id):
    invoice = Invoice.objects.get(id=invoice_id)

    pdf = df.from_template(
        template="tmpl_invoice_v2",
        data={
            "company": invoice.customer_name,
            "items": list(invoice.items.values("description", "qty", "rate")),
            "total": str(invoice.total),
        },
        output="base64",
    )

    import base64
    content = base64.b64decode(pdf.data)
    response = HttpResponse(content, content_type="application/pdf")
    response["Content-Disposition"] = f'attachment; filename="invoice-{invoice_id}.pdf"'
    return response

# urls.py
from django.urls import path
from . import views

urlpatterns = [
    path("api/generate/", views.generate_pdf),
    path("api/invoices/<int:invoice_id>/download/", views.download_invoice),
]