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The Bold Checkout APIs give you full control of your checkout. Use the APIs to customize the look and feel of your checkout to align with your brand, extend Bold Checkout's capabilities, and remove the friction from your customers’ checkout experience.

Checkout flows

Bold Checkout is designed around checkout flows (Patent Pending): optimized checkout experiences individually designed to serve a specific set of shoppers based user-defined criteria, such as the device they're using, their screen size, or the items in their cart.

Checkout flows fall broadly into two categories:

  • Hosted flows are built and hosted by Bold. These flows can be used without any development work.


    Bold currently supports the use of only one Bold-hosted flow at a time.

  • Custom flows are bespoke applications not hosted by Bold. These flows have custom frontends that take advantage of the Bold APIs to power the checkout. Bold supports the use of any number of custom flows at a time.

For more information about flows and their components, refer to the conceptual Checkout flows page.

Bold Checkout APIs

Bold offers a series of OpenAPI specifications that reflect our API capabilities:

APIAuthentication methodDescription
Checkout Backend APIAPI access tokenPerforms tasks such as initializing an order, adding an authenticated customer, and capturing payments.
Checkout Frontend APIJSON web token (JWT)Performs user-driven functions, such as adding and editing cart line items, editing billing and shipping addresses, and choosing a shipping method.
Checkout Admin APIAPI access tokenConfigures store-level settings, including overrides and external payment gateways.

Bold provides several other non-OpenAPI specifications, which outline the requests and responses of custom interfaces between a client and Bold:

  • Payment Isolation Gateway Interface (PIGI) API — The interface that a customer uses to input their payment information and add the payment method to an order. PIGI isolates customer payment information from everything else that happens during a checkout experience. This separation increases the security of the customer’s payment information by preventing any third party scripts from having access to information shoppers input into the payment fields.
  • External Payment Gateway Connector API and External Payment Gateway Actions and Events — The interfaces that Bold uses to communicate with an external payment gateway that is not already officially supported by Bold.
  • Plugin Events and Plugin Actions — The communication method between Bold Checkout and any plugins that integrate with it.

The content in this section of the Developer Documentation applies only to Bold Checkout APIs (called Bold Cashier on Shopify) that access The same applies to the Checkout Backend and Checkout Frontend API specifications.

If you are looking for earlier versions of the Bold Checkout APIs, which access, refer to the Bold Cashier API.

Extending Bold Checkout

You can use the Bold Checkout APIs to change and extend Checkout in a variety of ways. There are two primary mechanisms to do so:

  • Create an integration, which extends the functionality of Bold Checkout by using the Checkout Frontend and Checkout Backend APIs on
  • Create a plugin, which extends the functionality of Bold Checkout using events and actions.

The following table includes a variety of use cases and the mechanisms that enable them:

Use caseRecommended solution
Use data from the Bold webhooks to inform marketing strategy (i.e. sending custom abandoned cart emails).Integration
Check that all orders adhere to your area’s compliance requirements, and cancel orders that violate these requirements.Plugin or Integration
Add a one-time fee to every order, such as an eco fee, cleaning fee, etc.Plugin
Provide a discount if the customer’s purchase is above a certain threshold.Plugin
Create a bridge between Bold Checkout and a third-party tax provider.Plugin
Create a bridge between Bold Checkout and a third-party shipping provider.Plugin
Flag an order as Buy Online, Pickup In Store (BOPIS) and set the shipping address to the store where the order should be picked up.Plugin

If you are not sure whether your use case requires a plugin or an integration, reach out to [email protected].

Getting started

Ready to jump in? The Checkout Getting Started page gives you everything you need to know to begin using Bold APIs.