# Build custom checkout with Checkout OS

> Composable APIs for identity, payments, fraud, tax, and subscriptions when you control the checkout experience.

Source: https://help.boltapp.com/products/checkout-os

**Checkout OS** is Bolt's modular checkout platform: pick the APIs you need for identity, payments, fraud, and subscriptions without rebuilding billing infrastructure from scratch.

## Who this is for [#who-this-is-for]

SaaS companies, app developers, and headless commerce teams that own the checkout UI and need production-ready payment and identity APIs.

## How it works [#how-it-works]

1. Choose modules: identity, payments, fraud review, subscriptions, or the full stack.
2. Integrate Bolt APIs and embedded components into your checkout flow.
3. Bolt handles PCI scope, network shopper recognition, and payment routing.
4. Configure products, webhooks, and dashboard settings as you scale.

## Get started [#get-started]

| Task                                           | Link                                                                   |
| ---------------------------------------------- | ---------------------------------------------------------------------- |
| Payment fields and shopper accounts in your UI | [Embeddable Checkout](/products/embeddable-checkout)                   |
| Embeddable API guide                           | [Embeddable checkout guide](/api-reference/guides/embeddable-checkout) |
| Recurring billing APIs                         | [Subscriptions](/products/subscriptions)                               |
| Choose an integration path                     | [Choose an integration](/getting-started/choose-integration)           |

## Related [#related]

* [Custom Payments](/products/custom-payments)
* [Bolt for SaaS](/use-cases/saas)
* [Bolt for App Developers](/use-cases/app-developers)