Usage events, explained
July 16, 2026
Everything in this series — metering, entitlements, credits, the invoice itself — runs on one tiny thing: a usage event.
It's the smallest object in billing and the most consequential. Get it right and every pricing model is available to you. Get it wrong and no dashboard downstream can fix it.
What a usage event is
A usage event is a record that says: this customer did one countable thing, at this moment. An API call landed. A document was processed. A delivery was dispatched. A thousand tokens were generated.
That's the whole idea. Your product emits the event; the billing platform does everything after — counting it into meters, checking it against limits, debiting wallets, pricing it into invoice lines.
Anatomy of a good event
A well-designed event carries four things:
- Who — the customer (and if relevant, which of their workspaces or keys). Billing is per-customer; an event that can't be attributed can't be billed.
- What — the event name, from a small, deliberate vocabulary:
api_call,document_processed,tokens_generated. Resist inventing a name per feature; every name is a future pricing decision. - How much — a quantity, when one event represents many units: 1,412 tokens, 3.2 gigabytes. Default is one.
- A unique ID — so the same event sent twice (retries happen; networks fail) counts once. This property, idempotency, is the difference between a billing system and a lawsuit generator. If you remember one engineering detail from this series, make it this one.
Timestamps matter too — the event carries when it happened, not when it arrived, so a delayed batch lands in the right billing period.
Instrument before you price
The quiet superpower of usage events: you can send them before you bill on them. Instrument your product's countable actions today — even on flat-price plans — and you're accumulating the dataset that answers next year's hardest questions: What does a heavy user actually cost? Where should tiers break? What would hybrid pricing have earned last quarter?
Businesses that instrument early choose their pricing from evidence. Everyone else chooses it from a competitor's pricing page.
What this looks like in Tirdad
In Tirdad, the event is one call, and everything downstream is automatic:
- Send it from any stack — the TypeScript, Python, and Go SDKs, or the raw API. One small request per event.
- Meters aggregate in real time — the dashboard reflects new events within seconds, not at month-end.
- The same event drives everything — meters, entitlement checks, wallet debits, and invoice lines all read from one stream, so the numbers agree with each other by construction.
- Built for volume — the analytics behind it are designed for event streams, not spreadsheet exports.
One tiny record, sent once, honestly — and the rest of this series happens by itself.
This is billing, explained · 08 — and it completes the core eight. From here the series continues into pricing models, coupons, and the business of billing — follow along on the blog, or start from article one.
Ready to send your first event? Start free at tirdad.ai.