Usage-based billing & webhooks, built for modern SaaS
Track usage, configure pricing, generate invoices, and deliver billing events — using a production-grade, developer-first platform.
Designed with real-world SaaS architecture patterns.
POST /api/track
x-usageflow-api-key: uf_live_***
{
"metric": "API_CALL",
"amount": 1000,
"customerId": "user_123"
}What is UsageFlow?
UsageFlow is a multi-tenant SaaS platform that enables applications to track usage, apply pricing rules, generate invoices, and notify external systems through reliable webhooks.
It is designed to model real-world billing systems, focusing on event-driven architecture, background processing, and observability rather than simple UI workflows.
How It Works
UsageFlow follows a clear, event-driven flow from usage tracking to billing and delivery.
Track usage
Applications send usage events securely using API keys, recording metrics such as API calls or active users.
Apply pricing rules
Usage is aggregated in the background and priced according to configurable plans and metrics.
Generate invoices
Invoices are created automatically at the end of each billing period based on aggregated usage.
Deliver events
Important events such as invoice creation are emitted and delivered reliably to external systems via webhooks.
Key Features
Designed to reflect real-world SaaS billing and event-driven systems.
Multi-tenant architecture
Organizations are fully isolated with role-based access control and scoped data access.
Flexible pricing engine
Define metrics, plans, and overage rules to model usage-based pricing accurately.
Secure usage ingestion
Usage events are ingested via hashed API keys with strict validation and isolation.
Background processing
Usage aggregation, invoice generation, and webhook delivery run asynchronously via workers.
Reliable webhooks
Business events are stored durably and delivered with retries and delivery logs.
Auditability & observability
Sensitive actions and webhook deliveries are logged for traceability and debugging.
Architecture & Reliability
UsageFlow is built using an event-driven architecture designed for correctness and reliability. Business events such as usage aggregation, invoice generation, and webhook delivery are persisted and processed asynchronously using background workers.
Instead of coupling user actions directly to side effects, UsageFlow separates event creation from event processing, ensuring durability, observability, and safe retries.
This approach mirrors patterns used in production SaaS platforms handling billing and external integrations.
- Durable event storage
- Background workers with retries
- Delivery logs & audit trails
Explore UsageFlow in action
View the dashboard or explore the source code to understand how UsageFlow is built.