Checkout Extension Payments API
Checkout Extension Payments API
A checkout extension payments API for teams building installable extensions that need safe collection actions, hosted fallback, and order-backed payment context.
Teams searching checkout extension payment APIs usually need a way to plug into buyer collection flows without losing the order state, hosted fallback options, and post-payment meaning behind the checkout.
Flint gives checkout extensions a stronger backend model because hosted checkout, embedded flows, payment links, and refunds all stay on one order-backed platform.
Extensions can install through the public partner-app model and then operate against concrete checkout and order objects rather than approximating the sale from frontend events alone.
The same platform can support in-checkout behavior and later hosted recovery or support actions without switching systems.
Use This Platform Shape When
Your extension needs to influence buyer collection flows while still depending on a durable order and payment model underneath.
The checkout extension may need hosted fallback, remote collection, or post-purchase recovery without leaving the same platform.
You want installable extension auth plus checkout-state visibility to live on one public API family.
Hosted checkout extension logic
Build extension behavior around checkout sessions that already belong to one specific order instead of trying to infer the sale from frontend signals alone.
Embedded checkout plus extension hooks
Keep the buyer on the merchant frontend while the extension still relies on Flint's backend order and payment model for the hard parts.
Fallback after checkout drop-off
Hand an abandoned or interrupted buyer into payment links or other hosted recovery paths without changing the underlying workflow model.
Install, observe, act
Use partner-app install plus app-owned webhooks so the extension can react to the checkout and payment lifecycle cleanly after merchant approval.
Choose Something Narrower When
Implementation References
Reference the platform-level surfaces
Checkout Sessions API
Inspect the hosted checkout object model that stays tied to a specific order.
Embedded Payments Guide
Use this when extension logic needs to coexist with embedded checkout on the merchant frontend.
Partner Apps API
Use the app-install surface for extension registration, auth, and webhook ownership.
Related Pages
Explore hosted checkout, embedded pay, and broader extension architecture
These pages help split checkout-specific extension decisions from the wider ecommerce plugin and platform story.
Ecommerce Checkout API for Developers
Use this when the main decision is checkout architecture rather than installable extension behavior.
Hosted Checkout API for Developers
Use this when the current question is one order-backed hosted checkout flow rather than extension architecture broadly.
Ecommerce Plugin Payments API
Go broader when the plugin needs to operate across more than checkout-specific flows.