SaaS Billing & Subscription Platform
Multi-tenant billing engineered for messy real-world plans.
−95%
Manual fixes
<24h
Deal → billing
100%
Audit completeness
Overview
A subscription engine for a B2B SaaS handling annual prepay, mid-cycle upgrades, custom enterprise terms, and the inevitable usage-based add-on. Built as a service, used by every other surface.
The problem
Sales was selling deals that finance couldn't reconcile and engineering couldn't implement — coupons stacking with discounts stacking with usage tiers, all with different anchor dates.
Approach
- 01
Modeled billing as a state machine over a ledger — every change emits an entry, every invoice rebuilds from the ledger.
- 02
Ran cycle math inside Temporal workflows for idempotency and replayability across long-running renewals.
- 03
Built a sandbox simulator so sales could price a deal and finance could review the projected invoices before signature.
Outcome
Reduced manual invoice corrections from 60+ per month to fewer than 3.
Cut deal-to-billing time from 6 days (legal + finance + ops) to under 24 hours.
Audit-grade trail for every charge — finance can answer customer questions without paging engineering.