---
name: spree-checkout-f69739bd94ae
description: >
  Implement Spree's checkout — the Order state machine (cart → address →
  delivery → payment → confirm → complete), the Payment and Shipment sub-state
  machines, the return flow (ReturnAuthorization → CustomerReturn →
  Reimbursement → Refund), guest checkout, payment-step skipping for
  credit-covered orders, and the V3 checkout API surface. Use when building or
  customizing checkout flows, debugging state transitions, or wiring custom
  checkout steps.
---

# Spree Checkout

## Before writing code

**Fetch live docs**:
1. Fetch https://spreecommerce.org/docs/developer/core-concepts/orders for the canonical state machine.
2. Fetch https://spreecommerce.org/docs/developer/core-concepts/payments for the Payment + PaymentSession (v5.4+) flow.
3. Check the live `Spree::Order` source on GitHub for the `state_machine` block — transitions and callbacks change.
4. For headless checkout, fetch the v3 Store API docs at https://spreecommerce.org/docs/api-reference.
5. Verify any custom-step pattern against the latest examples in `spree-starter`.

## Conceptual Architecture

### The Order State Machine

```
cart → address → delivery → payment → confirm → complete
                                ↓
                              skip if store-credit-covered
```

Each transition validates prerequisites:

| State | Prerequisites |
|-------|---------------|
| `cart` | One or more line items |
| `address` | Bill + ship address present |
| `delivery` | Shipping method selected for every shipment |
| `payment` | At least one payment method valid for the total |
| `confirm` | Optional review step (configurable) |
| `complete` | All sub-states valid; transitions trigger fulfillment + emails |

### Payment Sub-State

`Order#payment_state` is a separate field summarizing all `Payment` rows:

| Value | Meaning |
|-------|---------|
| `balance_due` | Outstanding amount remains |
| `paid` | Fully paid |
| `credit_owed` | Refund pending |
| `failed` | All payments failed |
| `void` | Voided |

### Shipment Sub-State

`Order#shipment_state` summarizes all `Shipment` rows:

| Value | Meaning |
|-------|---------|
| `pending` | Awaiting payment / stock |
| `ready` | Ready to ship |
| `partial` | Some shipped |
| `shipped` | All shipped |
| `backorder` | Inventory shortfall |
| `canceled` | Canceled |

### Individual Shipment / Payment State Machines

- **`Shipment#state`**: `pending → ready → shipped` (+ `canceled`)
- **`Payment#state`**: `checkout → processing → pending → completed` (+ `failed`, `void`, `invalid`)

### Return Flow

```
ReturnAuthorization (authorized | canceled)
  → CustomerReturn
    → Reimbursement (pending | reimbursed | errored)
      → Refund (against original Payment)
```

`StoreCredit` reimbursements skip the Refund step and credit the user's balance.

### Skipping the Payment Step

If `order.outstanding_balance.zero?` after store-credit/gift-card application, the state machine skips `payment` and goes straight to `confirm`. Useful for free-trial / 100%-off scenarios.

### Guest vs Authenticated Checkout

Spree supports guest checkout by default — orders carry an `email` and `order_token` even without a `User`. The token allows a guest to revisit their order. Convert guests to users post-checkout via `Spree::Order#associate_user!`.

### Custom Checkout Steps

Add a custom step by inserting into the state machine via decorator:

```ruby
# app/models/spree/order_decorator.rb
module MyApp::OrderDecorator
  def self.prepended(base)
    base.state_machine.before_transition to: :delivery, do: :verify_gift_message
  end

  def verify_gift_message
    # …
  end

  Spree::Order.prepend(self)
end
```

Custom steps are powerful but **upgrade-fragile** — Spree's state machine evolves. Prefer events or service objects when you only need to react.

### Checkout via API v3 (v5.4+)

Headless checkout typically:

1. `POST /api/v3/store/cart` — create cart (returns `ord_…` ID + cart token)
2. `POST /api/v3/store/cart/line_items` — add items
3. `PUT /api/v3/store/checkout` — set addresses, shipping method, payment method
4. `POST /api/v3/store/checkout/payment_sessions` — create a PaymentSession (Stripe/Adyen/PayPal)
5. `POST /api/v3/store/checkout/complete` — finalize

(Verify exact paths in the v3 API reference — endpoint shapes are still settling.)

### Payment Sessions (v5.4+)

The v5.4 `PaymentSession` abstracts the payment-provider handshake. The storefront creates a PaymentSession, the user authorizes via the gateway's hosted UI (Stripe Elements, Adyen Drop-in, PayPal Checkout), and the session is captured into a `Payment` on completion. Provider-specific.

## Implementation Guidance

### Reading the Current State

```ruby
order.state                # one of cart/address/delivery/payment/confirm/complete
order.payment_state        # balance_due/paid/...
order.shipment_state       # pending/ready/...
order.can_transition?(:complete)  # check before triggering
```

### Triggering Transitions Programmatically

```ruby
order.next!     # advance to the next state if valid
order.complete! # force to complete if valid (typically last step)
order.cancel!   # cancel + revert inventory
```

Never call `update_attribute(:state, …)` directly — bypasses callbacks and corrupts inventory/payments.

### Subscribing to Checkout Events

```ruby
class CheckoutSubscriber < Spree::Subscriber
  subscribes_to 'order.completed'
  on 'order.completed', :send_welcome_email

  def send_welcome_email(event)
    return if event.order.user.nil?
    # …
  end
end
```

Events fire after the database commit — safe to enqueue background jobs.

### Headless Checkout Patterns

- **Always use httpOnly cookies for the cart/order token**, not localStorage.
- **Confirm the cart server-side before showing the review step** — prices, tax, shipping can change between page loads.
- **Idempotency-Key headers on `/complete`** — prevent double-charging on retry.
- **Use Payment Sessions for v5.4+** — they handle 3DS / SCA / Apple Pay / Google Pay uniformly.

### Debugging Stuck Transitions

```ruby
order.errors.full_messages
order.valid?(state)  # validate for a specific state
order.checkout_steps  # configured step list
```

### Returns Workflow

```ruby
ra = Spree::ReturnAuthorization.create!(order: order, return_items: items)
ra.authorize!
cr = Spree::CustomerReturn.create!(return_items: ra.return_items, stock_location: location)
cr.fully_received?
reimbursement = Spree::Reimbursement.create!(customer_return: cr, order: order)
reimbursement.perform!  # creates Refunds or StoreCredits
```

### Common Pitfalls

- **Bypassing the state machine** by setting `state` directly → corrupts inventory and payment totals.
- **Forgetting to recompute totals** after adjusting line items → use `Spree::OrderUpdater`.
- **Marking a Payment `completed` manually** → use the gateway's capture flow; manual completion skips reconciliation.
- **Treating `confirm` as required** — it's configurable (`checkout_steps` order).
- **Headless checkout drift** — the storefront's local state can diverge from the server's `Order#state`. Re-fetch after every mutating call.
- **Custom decorator on `state_machine`** — survives minor upgrades poorly; prefer event subscribers when possible.

Always re-verify state names and transition guards against the live `Spree::Order` source for the version you target.


---
Source attribution: OrcaQubits
Original project: https://github.com/OrcaQubits/agentic-commerce-skills-plugins/blob/30cd25c74c8aa7dc49b3ec4847d463f6104439f6/dist/codex/spree-commerce/skills/spree-checkout/SKILL.md
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Mega AI Hub.

## Upstream license notice

MIT License

Copyright (c) 2024-2026 OrcaQubits AI (https://orcaqubits-ai.com)

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.



# Mega AI Hub resource metadata

Creator / publisher: OrcaQubits
Original project: https://github.com/OrcaQubits/agentic-commerce-skills-plugins/blob/30cd25c74c8aa7dc49b3ec4847d463f6104439f6/dist/codex/spree-commerce/skills/spree-checkout/SKILL.md
Attribution basis: Source repository record

Fields of work: Development & Engineering, Product Management
Roles: Backend Developer, Growth Product Manager, Product Manager
Specialties: Backend
Tools: Spree
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: 690cad7a770073f0d0939e040638f72af6e2471b13b73ec175b50a8892a47e8c