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 → resumed3. 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
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.