Subscription billing

A subscription billing system holds the plan catalogue, the state of each customer's subscription (trialling, active, past due, cancelled), and the rules for moving between states. Every cycle it computes charges from plan fees plus metered usage, applies proration for mid-cycle changes, adds tax, generates an invoice and collects payment through a gateway. Retry schedules and dunning emails handle failed cards, which are a major hidden source of churn.

Indian SaaS companies face extra requirements: GST on domestic invoices with the customer's GSTIN, e-invoicing thresholds, RBI rules on recurring card mandates, UPI autopay for consumer plans, and USD invoicing for export customers. Gateways such as Razorpay or Stripe cover collection; the subscription logic, entitlement checks and accounting exports are usually product code or a billing platform layered on top.

Billing is not usage metering; metering counts, billing prices and invoices. It is also separate from entitlement (what a plan unlocks), though the two must stay in sync so that a downgrade removes access and an upgrade grants it immediately.

• CFO: billing correctness is revenue correctness; proration errors, missed tax and silent card failures all show up as leakage.
• Founder / CEO: pricing experiments, annual plans and enterprise contracts are only as flexible as the billing system allows.
• CTO / Head of Engineering: billing has more edge cases than any other subsystem and is the last place to write clever custom code.
• Operations head: invoices, credit notes and GST filings have to reconcile with the accounting system every month.

Subscription billing exists because recurring revenue has recurring complexity: plan changes mid-cycle, trials that convert or expire, taxes that vary by country and state, cards that expire and mandates that need renewal. A dedicated system handles these consistently so finance can trust the numbers. The trade-off is cost and lock-in with billing platforms versus the maintenance burden of building it yourself; most teams should buy the engine and build only the pricing model, entitlements and integrations.

• A B2B SaaS charging per seat monthly with a metered AI add-on billed in arrears.
• An Indian SaaS company issuing GST-compliant invoices to domestic customers and USD invoices to overseas ones.
• A D2C subscription box using UPI autopay mandates for recurring consumer payments.
• An education platform billing institutions annually while individual learners pay monthly.
• A telehealth service with per-consultation charges layered on a base membership fee.

Technique / practiceA domain with established platforms (Stripe Billing, Razorpay Subscriptions, Chargebee) plus product-specific logic for plans and entitlements. Eazyware integrates billing platforms and builds entitlement and metering logic under the SaaS development and API integrations services.

Eazyware service that covers it: SaaS / Cloud-native Application Development. Starting prices are on the pricing page.