Implementation Guides
Example integrations for the Usagey billing platform
These examples focus on the current billing platform model: plans, features, credit packs, billable customers, subscriptions, usage tracking, and environment-scoped API keys.
Plan and feature catalog
Start with plan groups, plans, and feature assignments so entitlements are deterministic before any usage arrives.
Customer and subscription state
Create billable customers separately from internal operators, then attach subscriptions and overrides.
Credit packs and add-ons
Use credit systems and packs when you want prepaid top-ups instead of pure overage billing.
Next.js SaaS Starter
A product-style demo for subscription checkout, billing portal handoff, usage tracking, and dashboard-driven billing operations.
- Calls `/v1/usage/track` and `/v1/usage/check` from a Next.js backend.
- Shows billing workspace setup for plans, features, and customers.
- Demonstrates subscription checkout and developer-event monitoring.
Express API Monetization Starter
An API-first reference for metered features, entitlement preflight checks, and customer-specific billing enforcement in Express.
- Tracks metered API requests with billing API keys.
- Checks entitlement state before expensive or credit-consuming operations.
- Illustrates how to separate app auth from billable customer identity.
What to test in your own integration
Validate the billing workflows that matter before switching production keys.
Verify sandbox plan creation, feature assignment, credit-pack purchase, and provider checkout callbacks.
Verify idempotent usage tracking, quota exhaustion, insufficient credits, and overage behavior for the features you meter.