Sardis Checkout Surface

Agentic Checkout - PSP routing and orchestration layer for Sardis.

This package provides the checkout surface that routes agent payments to existing PSPs (Stripe, PayPal, Coinbase, Circle) while leveraging the core Agent Wallet OS for policy enforcement and mandate verification.

Architecture

Agent Checkout Request
         │
         ▼
┌─────────────────────────────────────┐
│   Agent Wallet OS (Core)            │
│   - Policy Check                    │
│   - Mandate Verification            │
│   - Agent Identity                  │
└──────────────┬──────────────────────┘
               │
               ▼
┌─────────────────────────────────────┐
│   Checkout Orchestrator             │
│   - PSP Selection                   │
│   - Session Management              │
└──────────────┬──────────────────────┘
               │
        ┌──────┴──────┐
        │             │
        ▼             ▼
┌──────────┐   ┌──────────┐
│ Stripe   │   │ PayPal   │
│ Connector│   │ Connector│
└──────────┘   └──────────┘

Features

• Multi-PSP Support: Route to Stripe, PayPal, Coinbase, Circle
• Policy-Based Routing: Uses core policy engine for approval
• Checkout Sessions: Create and manage checkout sessions
• Webhook Handling: Process PSP webhooks
• Merchant Dashboard: Analytics and configuration

Installation

pip install sardis-checkout

Usage

Basic Checkout Flow

from sardis_checkout import CheckoutOrchestrator
from sardis_checkout.connectors import StripeConnector

# Initialize orchestrator
orchestrator = CheckoutOrchestrator(
    stripe_connector=StripeConnector(api_key="sk_..."),
)

# Create checkout session
session = await orchestrator.create_checkout_session(
    agent_id="agent_123",
    merchant_id="merchant_456",
    amount=Decimal("100.00"),
    currency="USD",
    metadata={"order_id": "order_789"},
)

# Get checkout URL
print(session.checkout_url)  # https://checkout.stripe.com/...

PSP Selection

# Orchestrator automatically selects PSP based on:
# 1. Merchant preference
# 2. Agent policy constraints
# 3. PSP availability

psp = await orchestrator.select_psp(
    merchant_id="merchant_456",
    agent_id="agent_123",
    amount=Decimal("100.00"),
)

Webhook Handling

from sardis_checkout.webhooks import handle_stripe_webhook

# Handle Stripe webhook
event = await handle_stripe_webhook(
    payload=request.body,
    signature=request.headers["stripe-signature"],
    secret=stripe_webhook_secret,
)

if event.type == "checkout.session.completed":
    # Update ledger, emit webhook, etc.
    await process_payment_completion(event.data)

Connectors

Stripe

from sardis_checkout.connectors.stripe import StripeConnector

connector = StripeConnector(
    api_key="sk_test_...",
    webhook_secret="whsec_...",
)

session = await connector.create_checkout_session(
    amount=Decimal("100.00"),
    currency="USD",
    agent_id="agent_123",
    metadata={},
)

PayPal (Coming Soon)

from sardis_checkout.connectors.paypal import PayPalConnector

connector = PayPalConnector(
    client_id="...",
    client_secret="...",
)

Coinbase Commerce (Coming Soon)

from sardis_checkout.connectors.coinbase import CoinbaseConnector

connector = CoinbaseConnector(
    api_key="...",
)

API Integration

FastAPI Router

from sardis_checkout.api import create_checkout_router

app.include_router(
    create_checkout_router(orchestrator),
    prefix="/api/v2/checkout",
    tags=["checkout"],
)

Endpoints

• POST /checkout/create - Create checkout session
• GET /checkout/{id} - Get checkout status
• POST /checkout/{id}/complete - Complete checkout
• POST /checkout/webhooks/{psp} - PSP webhook handler

Development

# Install dependencies
pip install -e ".[dev]"

# Run tests
pytest

# Type check
mypy src/

# Lint
ruff check src/

License

Proprietary - All rights reserved.