Technical Glossary

• Metering: The process of tracking, recording, and attributing real-time resource consumption (API calls, storage, compute seconds) to specific tenants and customers.
• Rating: The mathematical translation of raw consumption units into monetary currency according to contract rules, pricing tiers, and discounts.
• Idempotency Key: A unique client-generated token accompanying a request, ensuring that retried network submissions do not cause duplicate processing or double-billing.
• Graduated (Bracket) Pricing: A tiered pricing structure where usage is sliced across progressive thresholds, with different unit rates applied to each successive volume bracket.
• Volume Pricing: A pricing model where the total volume achieved over the billing period determines a single discounted rate applied to all consumed units.
• Overage Pricing: A hybrid model offering a fixed base fee covering an included quantity of units, with excess consumption billed at a specified overage rate.
• Double-Entry Bookkeeping: An accounting system where every financial transaction consists of at least two entries, guaranteeing that the sum of debits strictly equals the sum of credits.
• Gapless Sequential Numbering: A legal requirement in fiscal accounting ensuring that invoice numbers follow an unbroken arithmetic sequence (e.g., INV-2026-0001, INV-2026-0002) with no missing numbers.
• Dunning: The automated process of communicating with customers and scheduling payment retries to collect outstanding balances on past-due invoices.
• Proration: The proportional allocation of subscription charges or credits based on the exact elapsed time when a customer changes plans mid-cycle.
• Row-Level Security (RLS): A database security mechanism restricting data access to rows matching the authenticated tenant's identity.
• Differential Testing: A software testing technique where the output of an optimized operational system (e.g. pre-aggregated rollups) is verified against an unoptimized reference implementation (e.g. from-scratch SQL sums).
• MRR (Monthly Recurring Revenue): The predictable recurring revenue generated by active customer subscriptions normalized to a monthly interval.
• ARR (Annual Recurring Revenue): The annualized value of recurring customer subscriptions ($\text{MRR} \times 12$).