# Kwit

> Payment-provider-agnostic subscription billing for SaaS — products, subscriptions, invoices (Swiss QR Bill), usage metering, dunning, and a public REST API.

Kwit is the billing engine on top of processors such as zahls.ch. Integrate via `@kwit/sdk` or `Authorization: Bearer kwit_live_…` against `https://api.kwit.dev/v1`.

## Documentation

- [Changelog](https://docs.kwit.dev/docs/changelog): Platform release notes
- [Authentication](https://docs.kwit.dev/docs/api/authentication): API keys and request security
- [Checkout links API](https://docs.kwit.dev/docs/api/checkout-links): Reusable hosted checkout URLs
- [Checkout API](https://docs.kwit.dev/docs/api/checkout): POST /v1/checkout and GET /v1/checkout/:sessionId
- [Customers API](https://docs.kwit.dev/docs/api/customers): POST /v1/customers and customer usage endpoints
- [Discounts API](https://docs.kwit.dev/docs/api/discounts): Create, retrieve, and validate discount codes
- [Errors](https://docs.kwit.dev/docs/api/errors): HTTP status codes and SDK error handling
- [API v1 overview](https://docs.kwit.dev/docs/api): Base URL, authentication, and endpoint map
- [Portal API](https://docs.kwit.dev/docs/api/portal): POST /v1/portal/sessions
- [Products API](https://docs.kwit.dev/docs/api/products): CRUD and list endpoints for products
- [Subscriptions API](https://docs.kwit.dev/docs/api/subscriptions): Create, retrieve, and cancel subscriptions
- [Usage billing API](https://docs.kwit.dev/docs/api/usage-billing): Meters, events ingest, and meter management
- [Architecture](https://docs.kwit.dev/docs/main/architecture): How the Kwit platform is structured and how data flows
- [Core concepts](https://docs.kwit.dev/docs/main/concepts): Organizations, customers, collection methods, and hosted sessions
- [Getting started](https://docs.kwit.dev/docs/main/getting-started): Set up your organization and make your first API call
- [Welcome to Kwit](https://docs.kwit.dev/docs/main): Subscription billing platform for SaaS - products, invoices, dunning, and developer APIs
- [Checkout](https://docs.kwit.dev/docs/services/checkout): Hosted checkout sessions and reusable checkout links
- [Customers](https://docs.kwit.dev/docs/services/customers): End-customer records and collection methods
- [Dunning](https://docs.kwit.dev/docs/services/dunning): Retries, reminders, and subscription recovery when payments fail
- [Services overview](https://docs.kwit.dev/docs/services): Product documentation by billing domain
- [Invoices](https://docs.kwit.dev/docs/services/invoices): Invoice generation, delivery, and Swiss QR Bill
- [Payments](https://docs.kwit.dev/docs/services/payments): Card collection via zahls and offline QR / bank transfer
- [Products](https://docs.kwit.dev/docs/services/products): Catalog, pricing types, and billing intervals
- [Subscriptions](https://docs.kwit.dev/docs/services/subscriptions): Recurring billing lifecycle and cancellation
- [Usage billing](https://docs.kwit.dev/docs/services/usage-billing): Meters, event ingestion, credits, and product meter prices
- [Webhooks](https://docs.kwit.dev/docs/services/webhooks): Receive billing events in your application
- [Contact](https://docs.kwit.dev/docs/support/contact): Reach the Kwit team
- [Support](https://docs.kwit.dev/docs/support): How to get help with Kwit

## API base

- Production: `https://api.kwit.dev/v1`
- Auth: `Authorization: Bearer <api_key>`

## SDK

- npm: `@kwit/sdk`
- Full machine-readable index: `/llms-full.txt`