Ad-hoc pricing

Ad-hoc pricing lets you override a product’s price for one checkout. You keep selling an existing catalog product, but the price for that session is whatever you set on the cart item. Bachs never creates a new product, and your catalog price is untouched. Reach for it when the price is decided at order time rather than in your catalog: a negotiated deal, a customer-specific rate, a computed or usage-derived amount, or a one-off discount. The catalog stays clean; the override lives on the checkout. This lets you price in real time and still keep a clean catalog.

Before you start

A sandbox API key (sk_sandbox_...). See Authentication.
A catalog product to override. See Create a product.

Everything below uses the sandbox base URL, so you can run the whole flow without moving real money.

How it works

Add a pricing object to a product_cart item. Bachs charges the override instead of the product’s catalog price for that checkout only.

curl https://sandbox-api.bachs.io/v1/checkout-sessions \
  -H "Authorization: Bearer $BACHS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "product_cart": [
      {
        "product_id": "prod_abc123",
        "quantity": 1,
        "pricing": { "price_type": "fixed", "amount": "19.00" }
      }
    ],
    "customer": { "email": "jane@example.com" }
  }'

{
  "checkout_id": "chk_2N3o4P5q6R7s8T9u",
  "status": "open",
  "source_type": "CHECKOUT_SESSION",
  "amount": "19.00",
  "currency": "USD",
  "checkout_url": "https://checkout.bachs.io/c/V8xQ2mZpLj9RfTa",
  "products": [
    {
      "product_id": "prod_abc123",
      "quantity": 1,
      "unit_amount": "19.00",
      "currency": "USD",
      "price_type": "fixed",
      "line_total": "19.00"
    }
  ]
}

The override is in the product’s primary currency and applies to that checkout only. From here the flow is the ordinary checkout: redirect the customer to checkout_url and confirm with the collection.succeeded webhook. See Accept a payment with Checkout.

Price types

Ad-hoc pricing supports the same price types as catalog prices, with one exception.

`price_type`	What it does
`fixed`	A set amount. Put it in `pricing.amount`.
`custom`	Pay-what-you-want, bounded by `minimum_amount` / `maximum_amount` with an optional `preset_amount`.
`free`	No charge. The line is $0; the checkout completes without payment. On a recurring product it creates a free subscription (no card, renews with no charge).

A custom override lets the buyer choose the amount on the hosted checkout page, within your bounds:

curl https://sandbox-api.bachs.io/v1/checkout-sessions \
  -H "Authorization: Bearer $BACHS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "product_cart": [
      {
        "product_id": "prod_abc123",
        "quantity": 1,
        "pricing": {
          "price_type": "custom",
          "preset_amount": "10.00",
          "minimum_amount": "5.00",
          "maximum_amount": "100.00"
        }
      }
    ],
    "customer": { "email": "jane@example.com" }
  }'

The response shows the line as price_type: "custom" with the bounds, priced at the preset until the buyer changes it.

On a custom ui_mode checkout (server-to-server, your own UI) there is no hosted page to collect the amount. Send the buyer’s chosen amount as the cart item’s amount when you create the checkout.

One-time vs recurring

The override behaves differently depending on whether the product is one-time or recurring, but in both cases it stays out of your catalog price list.

One-time product. The override is snapshotted on the checkout. No price row is created; nothing changes in your catalog.
Recurring product. The override becomes the subscription’s price for its whole life. When the subscription activates, Bachs stores the settled amount as an archived, one-off price the subscription ties to.

An ad-hoc price is a one-off. It is never returned by the product price list and cannot be reused across checkouts. To sell at a price repeatedly, add it to the catalog instead.

Testing

Use a sandbox key (sk_sandbox_...) to run the whole flow against test-mode products without moving real funds. See Sandbox.

Next steps

Accept a payment with Checkout: the full checkout flow ad-hoc pricing plugs into, including charging a raw amount with no product at all.
Subscriptions: how a recurring ad-hoc price renews.
The checkout session object: every field the API accepts and returns.

Get Started

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For You and Your Customers

Ad-hoc pricing

Before you start

How it works

Price types

One-time vs recurring

Testing

Next steps

​Before you start

​How it works

​Price types

​One-time vs recurring

​Testing

​Next steps

Before you start

How it works

Price types

One-time vs recurring

Testing

Next steps