BNPL Payments API for Platforms

A BNPL payments API for platforms that want Affirm in checkout without building a separate billing abstraction or payment model beside the core API.

Flint exposes allowed payment method types on the public payment surface, including Affirm, instead of forcing a disconnected BNPL product layer.

BNPL can sit inside the same order-backed checkout and payment-intent flow as card and link payment methods.

Teams can add another checkout method without giving up the same order, refund, and support model used elsewhere.

Workflow Outline

You want to offer Affirm in checkout without creating a separate financing-specific billing layer.

Your team wants BNPL to appear as just another allowed payment method inside the same order-backed checkout flow.

You need support, refund, and order state to stay in the same model regardless of which method the buyer picks.

What This Solves

Teams searching BNPL or Affirm APIs usually want to offer another payment method inside checkout without fragmenting the rest of the order and billing model.

Step 1

Checkout method expansion

Add Affirm beside card and link without forking the rest of the order-backed checkout implementation.

Step 2

Platform-configured payment methods

Control which methods are allowed in checkout through the same public settings and payment configuration surface.

Step 3

Unified support model

Keep refunds, payment state, and buyer support anchored to one order model even when checkout includes BNPL.

Step 4

Hosted checkout with BNPL

Expose BNPL in the same hosted checkout session rather than sending buyers through a disconnected second payment experience.

Why Flint Fits

Flint exposes allowed payment method types on the public payment surface, including Affirm, instead of forcing a disconnected BNPL product layer.

BNPL can sit inside the same order-backed checkout and payment-intent flow as card and link payment methods.

Teams can add another checkout method without giving up the same order, refund, and support model used elsewhere.

Choose Another Path When

Use the broader payment API page when BNPL is only one method inside a wider payment-platform decision.

Use saved-payment-method pages when the product problem is later billing and reusable credentials, not checkout-time financing.

Use hosted-checkout pages when the main decision is the buyer payment surface rather than the payment methods inside it.

Implementation References

Reference the exact flow surfaces

Payments API

Review allowed payment methods on payment intents, including card, affirm, and link.

Settings API

Inspect checkout configuration and allowed payment method types such as affirm.

Checkout Sessions API

Use order-backed hosted checkout when BNPL should appear inside the same buyer payment flow.

Explore checkout methods, hosted flows, and adjacent payment surfaces

These pages help place BNPL inside Flint's wider checkout and payment model instead of treating it as a special-case stack.

Hosted Checkout API for Developers

Use this when the main decision is the hosted buyer payment surface, not just which methods appear inside it.

Payment API

Go broader when BNPL is only one capability inside a wider developer payment decision.

Saved Payment Methods API for Platforms

Use this when the core issue is reusable payment credentials and later billing, not checkout-time financing options.

Next Step

Ship the workflow before polishing the edge cases

Start with the underlying Flint flow, then layer your product-specific UX and recovery paths on top.