# Nomba Subscriptions Engine

> Developer documentation for integrating Nomba Subscriptions Engine: plans, customers, subscriptions, checkout, tokenized cards, invoices, and webhooks.

## Docs

- [Auth](https://nombasub.mintlify.app/api-reference/auth.md): Register and log in tenants to obtain API keys.
- [Checkout](https://nombasub.mintlify.app/api-reference/checkout.md): Initialize Nomba Checkout for card-backed subscription payments.
- [Customers](https://nombasub.mintlify.app/api-reference/customers.md): Create, list, retrieve, and update customers.
- [Plans](https://nombasub.mintlify.app/api-reference/plans.md): Create, list, retrieve, and update subscription plans.
- [Subscriptions](https://nombasub.mintlify.app/api-reference/subscriptions.md): Create and retrieve customer subscriptions.
- [Webhook Endpoints](https://nombasub.mintlify.app/api-reference/webhook-endpoints.md): Configure merchant webhook delivery.
- [Authentication](https://nombasub.mintlify.app/authentication.md): Authenticate server-side requests with tenant API keys.
- [Customers](https://nombasub.mintlify.app/core-concepts/customers.md): Represent the end users being billed by a tenant.
- [How the Engine Works](https://nombasub.mintlify.app/core-concepts/how-the-engine-works.md): Understand the managed billing architecture and Nomba-powered payment flow.
- [Invoice States](https://nombasub.mintlify.app/core-concepts/invoice-states.md): Implemented invoice statuses and billing lifecycle transitions.
- [Payment Sources](https://nombasub.mintlify.app/core-concepts/payment-sources.md): Store reusable card token references for recurring billing.
- [Plans](https://nombasub.mintlify.app/core-concepts/plans.md): Define subscription pricing, intervals, trials, and plan versions.
- [Subscription States](https://nombasub.mintlify.app/core-concepts/subscription-states.md): Implemented subscription statuses and transitions.
- [Subscriptions](https://nombasub.mintlify.app/core-concepts/subscriptions.md): Manage recurring billing relationships between customers and plans.
- [Tenants](https://nombasub.mintlify.app/core-concepts/tenants.md): How businesses are represented and authenticated in the engine.
- [Create a Card-backed Subscription](https://nombasub.mintlify.app/guides/card-backed-subscription.md): Create a plan, customer, checkout order, tokenized card, and recurring subscription flow.
- [Charge a Tokenized Card](https://nombasub.mintlify.app/guides/charge-tokenized-card.md): How due invoices use saved Nomba card tokens for renewals.
- [Configure Merchant Webhooks](https://nombasub.mintlify.app/guides/configure-merchant-webhooks.md): Receive normalized subscription and invoice events from the engine.
- [Handle Nomba Webhooks](https://nombasub.mintlify.app/guides/handle-nomba-webhooks.md): How the internal Nomba webhook endpoint updates billing state.
- [Nomba Integration](https://nombasub.mintlify.app/guides/nomba-integration.md): How the engine uses Nomba internally for checkout, tokenized cards, and webhooks.
- [Test the Billing Flow](https://nombasub.mintlify.app/guides/test-billing-flow.md): Run the MVP billing flow locally or in a sandbox-like environment.
- [Webhooks](https://nombasub.mintlify.app/guides/webhooks.md): Normalized merchant webhook events sent by the Subscriptions Engine.
- [Introduction](https://nombasub.mintlify.app/index.md): Welcome to your project
- [Billing Lifecycle](https://nombasub.mintlify.app/internals/billing-lifecycle.md): Internal invoice, trial, renewal, and payment attempt processing.
- [Data Model](https://nombasub.mintlify.app/internals/data-model.md): Internal tables and domain objects used by the billing engine.
- [Nomba Processing](https://nombasub.mintlify.app/internals/nomba-processing.md): Internal checkout, tokenization, charge, and webhook mapping behavior.
- [Webhook Delivery](https://nombasub.mintlify.app/internals/webhook-delivery.md): Internal outgoing webhook envelope, headers, signing, retries, and event data mapping.
- [Error Handling](https://nombasub.mintlify.app/operations/error-handling.md): Understand API error responses and recommended handling.
- [Pagination and Filtering](https://nombasub.mintlify.app/operations/pagination-filtering.md): Use page-based pagination and available filters.
- [Production Checklist](https://nombasub.mintlify.app/operations/production-checklist.md): Prepare your subscription integration for live billing.
- [Sandbox Testing](https://nombasub.mintlify.app/operations/sandbox-testing.md): Recommended test flow for subscription billing integrations.
- [Webhook Security](https://nombasub.mintlify.app/operations/webhook-security.md): Verify and safely process merchant webhooks.
- [Quickstart](https://nombasub.mintlify.app/quickstart.md): Begin with a guide on the fastest path to a successful outcome