"5 Python Libraries That Power My Self-Hosted Billing Monitor"

5 Python Libraries That Power My Self-Hosted Billing Monitor When I started building BillingWatch, I had one goal: catch billing anomalies before they become customer support nightmares. A refund tsunami at 2 AM. A webhook that quietly stops firing. Subscriptions flipping to "canceled" for no obvious reason. The commercial tools — Baremetrics, ChartMogul, Datadog — can do this, but they run $50–$400/month and you're trusting a third party with your entire billing data. I wanted something self-hosted, auditable, and free to run. Here are the 5 Python libraries that made BillingWatch work. 1. stripe — The Foundation pip install stripe Stripe's official Python SDK is the backbone of the whole system. BillingWatch uses it for two things: pulling historical event data for backfill and verifying webhook signatures so we know events are actually from Stripe. The signature verification piece is critical: import stripe def handle_webhook(payload: bytes, sig_header: str) -> dict: try: event =