Checkout V2

Beta — Checkout V2 is rolling out now. The session endpoints below are tagged Checkout V2 (Beta) in the API.

What's New: A Session-Oriented Checkout

Checkout V2 introduces a session-oriented model. Instead of creating a payment up front, a checkout now starts with a Checkout Session — a short-lived object that represents your customer's intent to pay.

The key difference from the previous flow:

You create a session first, and get back a hosted checkoutUrl.
The actual Payment is only created when the customer submits a payment method on the checkout page. For subscriptions, the Subscription and its first payment are created at that same moment.

This keeps your records clean (no half-finished payments) and lets the hosted page own the entire payment experience.

Sessions are temporary. You can control how long a session stays valid with expiresIn (in hours); if you don't set it, a session expires about 1 hour after creation.

Two Ways to Create a Session

There are two API endpoints for creating a payment session, depending on whether you're charging once or setting up recurring billing. Both use your private API key and the standard API host https://api.inflowpay.xyz (see Base URLs & Request Format).

Both endpoints return the same shape on success (201 Created):

{
  "sessionId": "sess_abc123",
  "checkoutUrl": "https://checkout.inflowpay.com/pay/sess_abc123"
}

Redirect your customer to the checkoutUrl to complete the payment.

One-Time Payment

Use this when you want to charge a customer once. You pass the products and currency directly in the request — no need to create a link or offer first.

POST /api/checkout/sessions/one-time-payment

Field	Required	Description
`currency`	Yes	`EUR` or `USD`
`products`	Yes	List of items to charge for (`name`, `price` in cents, `quantity`)
`successUrl`	No	Where the customer returns after a successful payment
`cancelUrl`	No	Where the customer returns if they abandon checkout
`customerEmail`	No	Pre-fills the customer's email
`expiresIn`	No	Hours until the session expires (minimum `0.25` = 15 minutes)

curl -X POST https://api.inflowpay.xyz/api/checkout/sessions/one-time-payment \
  -H "Content-Type: application/json" \
  -H "X-Inflow-Api-Key: inflow_prod_your_key" \
  -d '{
    "currency": "EUR",
    "products": [{ "name": "Premium Plan", "price": 4999, "quantity": 1 }],
    "successUrl": "https://yoursite.com/success",
    "customerEmail": "[email protected]"
  }'

Subscription

Use this to start a recurring subscription from an existing Subscription Offer. Create the offer first (from the Dashboard or API), then create a session for it. See Subscription Overview to learn about offers.

POST /api/checkout/sessions/subscription/{subscriptionOfferId}

Field	Required	Description
`successUrl`	No	Overrides the offer's default success URL
`cancelUrl`	No	Overrides the offer's default cancel URL
`customerEmail`	No	Pre-fills the customer's email
`expiresIn`	No	Hours until the session expires (minimum `0.25` = 15 minutes)

curl -X POST https://api.inflowpay.xyz/api/checkout/sessions/subscription/sub_offer_abc123 \
  -H "Content-Type: application/json" \
  -H "X-Inflow-Api-Key: inflow_prod_your_key" \
  -d '{
    "customerEmail": "[email protected]"
  }'

Checkout URLs

Your customers reach the hosted checkout through one of these URLs. Payment links and subscription links resolve into a Checkout V2 session, which is served on the /pay/{sessionId} page.

Use Case	URL Format
Payment link	`checkout.inflowpay.com/l/{linkId}`
Subscription link	`checkout.inflowpay.com/subscribe/{offerId}`
Checkout session (returned by the APIs above)	`checkout.inflowpay.com/pay/{sessionId}`

Payment and subscription links are still the easiest way to share a checkout — they're generated automatically when you create a link or an offer. The session endpoints are for when you want to create the checkout dynamically from your backend.

Next Steps

Checkout Interface Overview — what your customers see on the hosted page.
Session Customization — brand the checkout with your colors, logo, and name.
Subscription Overview — create and manage recurring billing offers.