> For the complete documentation index, see [llms.txt](https://bagelpay.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://bagelpay.gitbook.io/docs/documentation/developers-and-api-usage.md).

# Developers & API Usage

- [Developer Integration Guide](https://bagelpay.gitbook.io/docs/documentation/developers-and-api-usage/developer-integration-guide.md)
- [Products](https://bagelpay.gitbook.io/docs/documentation/developers-and-api-usage/products.md): This document provides details on how to create, update, manage, and retrieve one-time or subscription-based products using the Bagel Payments API.  ​
- [Checkout Session](https://bagelpay.gitbook.io/docs/documentation/developers-and-api-usage/checkout-session.md): Checkout Session API enables merchants to easily integrate secure online checkout and payment into their systems, streamlining order processing and automatically updating payment status via webhooks.
- [Transactions](https://bagelpay.gitbook.io/docs/documentation/developers-and-api-usage/transactions.md)
- [Subscription](https://bagelpay.gitbook.io/docs/documentation/developers-and-api-usage/subscription.md)
- [Billing](https://bagelpay.gitbook.io/docs/documentation/developers-and-api-usage/billing.md)
- [Customers](https://bagelpay.gitbook.io/docs/documentation/developers-and-api-usage/customers.md)
- [Customer Portal](https://bagelpay.gitbook.io/docs/documentation/developers-and-api-usage/customers/customer-portal.md): Customers can cancel and refund subscriptions by themselves.
- [Webhooks](https://bagelpay.gitbook.io/docs/documentation/developers-and-api-usage/webhooks.md)
- [Webhook User Guide](https://bagelpay.gitbook.io/docs/documentation/developers-and-api-usage/webhooks/webhook-user-guide.md): Use webhooks to notify your application about payment events.
- [Event Types](https://bagelpay.gitbook.io/docs/documentation/developers-and-api-usage/webhooks/event-types.md): List of supported event types and their payloads.
- [Verify Webhook Requests](https://bagelpay.gitbook.io/docs/documentation/developers-and-api-usage/webhooks/verify-webhook-requests.md): How to verify BagelPay signature on webhook objects.