先看看示例
作者提供的示例，实际效果取决于你的输入和使用工具。
输入
为 cus_123 创建 14 天试用的月度 Pro 订阅，并在周期结束时生成发票、对失败扣款启动重试。
输出
预期交付：订阅对象与计费周期处理结果，含发票、按比例费用与催收流程状态。（编辑说明，非实际运行结果）
方法说明
---
name: billing-automation
description: Build automated billing systems for recurring payments, invoicing, subscription lifecycle, and dunning management. Use when implementing subscription billing, automating invoicing, or managing recurring payment systems.
---
# Billing Automation
Master automated billing systems including recurring billing, invoice generation, dunning management, proration, and tax calculation.
## When to Use This Skill
- Implementing SaaS subscription billing
- Automating invoice generation and delivery
- Managing failed payment recovery (dunning)
- Calculating prorated charges for plan changes
- Handling sales tax, VAT, and GST
- Processing usage-based billing
- Managing billing cycles and renewals
## Core Concepts
### 1. Billing Cycles
**Common Intervals:**
- Monthly (most common for SaaS)
- Annual (discounted long-term)
- Quarterly
- Weekly
- Custom (usage-based, per-seat)
### 2. Subscription States
```
trial → active → past_due → canceled
→ paused → resumed
```
### 3. Dunning Management
Automated process to recover failed payments through:
- Retry schedules
- Customer notifications
- Grace periods
- Account restrictions
### 4. Proration
Adjusting charges when:
- Upgrading/downgrading mid-cycle
- Adding/removing seats
- Changing billing frequency
## Quick Start
```python
from billing import BillingEngine, Subscription
# Initialize billing engine
billing = BillingEngine()
# Create subscription
subscription = billing.create_subscription(
customer_id="cus_123",
plan_id="plan_pro_monthly",
billing_cycle_anchor=datetime.now(),
trial_days=14
)
# Process billing cycle
billing.process_billing_cycle(subscription.id)
```
## Detailed patterns and worked examples
Detailed pattern documentation lives in `references/details.md`. Read that file when the navigation tier above is insufficient.