ChaChing.io is a smart billing layer in 2026 that slashes subscription fees by ~50% while letting you keep Stripe (or similar) for actual payments. It handles automated subscriptions, invoicing, prorations, global tax compliance (via pluggable engines like TaxJar), real-time MRR/ARR/LTV analytics, smart ML retries, customer portals, and zero-downtime migrations from Stripe Billing/Chargebee. Perfect for SaaS founders, subscription businesses, and growing teams tired of high billing taxes—simple, PCI/SOC2 secure, and developer-friendly with OpenAPI.