Short answer
A SaaS billing and subscription system manages plans, trials, upgrades and downgrades, seat and usage-based pricing, invoices, taxes, payment retries and revenue reporting. Infikey builds billing on top of Stripe Billing, Razorpay Subscriptions, Chargebee or Paddle, or a custom engine for complex pricing. Typical builds cost USD 15,000–60,000 depending on pricing complexity and markets.
Updated · Written by the Infikey Technologies delivery team
Billing features
| Area | Features |
|---|---|
| Plans | Monthly and annual plans, add-ons, free trials, coupons, grandfathered prices |
| Usage | Metering events, aggregation, included allowances, overage pricing |
| Changes | Upgrades, downgrades, seat changes with proration, pauses and cancellations |
| Payments | Cards, UPI AutoPay, direct debit, invoices with bank transfer for enterprise |
| Recovery | Smart retries, card updater, dunning emails, grace periods |
| Invoices and tax | Compliant invoices, GST and VAT numbers, reverse charge, US sales tax through a tax engine |
| Reporting | MRR, ARR, churn, expansion revenue, deferred revenue exports |
Buy a billing platform or build your own?
- Use Stripe Billing, Razorpay Subscriptions, Chargebee or Paddle for standard plans and seats. We integrate them deeply: in-app plan pages, entitlements, webhooks and reporting.
- Build a custom rating engine when pricing depends on complex usage (API calls, compute, records processed), contracts with negotiated rates, or several payment providers by market.
- Merchant of record services such as Paddle handle global sales tax for you, at a higher fee.
Most products combine a provider for payments and invoices with custom entitlement logic in the app. Track the results with the SaaS metrics calculator, and see payment gateway integration for multi-gateway setups.
Cost
| Scope | Budget (USD) | Budget (INR) |
|---|---|---|
| Plans, trials and checkout on one provider | 15,000–25,000 | 12–20 lakh |
| Seats, usage metering, dunning and revenue reports | 25,000–45,000 | 20–37 lakh |
| Custom rating engine with multiple providers and enterprise contracts | 40,000–60,000+ | 32–50 lakh+ |
These are planning ranges, not quotes.
Project blueprint
Usage-based billing for an API product
Based on the requirements we hear most often from buyers like this.
An API company charges customers a flat monthly fee, while heavy users cost far more to serve than light ones. It wants usage-based pricing with included allowances, but its current billing setup only supports fixed plans.
What we would build
- Usage metering from API gateway events, aggregated per customer
- Plans with included allowances, overage tiers and annual commitments
- Stripe Billing integration for invoices, cards and bank transfers
- Customer dashboard showing usage, projected bill and alerts
- Revenue reports for MRR, expansion and churn
How success is measured
- Revenue per customer and expansion revenue
- Gross margin per customer segment
- Billing disputes and manual invoice corrections
- Failed payment recovery rate