---
name: domain-ecommerce-cart-checkout-a7309e5022fd
description: |
  Shopping cart and checkout flow design: cart architectures (session, DB, Redis, headless cart APIs),
  express checkout (Apple Pay, Google Pay, Shop Pay, Amazon Pay), shipping integration (ShipStation,
  Shippo, EasyPost), tax engines (Avalara, TaxJar), promotion/discount engine, cart recovery
  (Klaviyo, Omnisend), BOPIS (buy online pick up in-store), guest checkout, address validation,
  and checkout conversion optimization.
allowed-tools: Read, Grep, Glob, Bash
---

# Cart and Checkout

## When to use
- Designing or rebuilding a shopping cart (storage strategy, data model, merge logic)
- Implementing express checkout methods (Apple Pay, Google Pay, Shop Pay, Amazon Pay)
- Building or integrating a checkout flow (single-page, multi-step, guest checkout)
- Wiring up shipping aggregators or tax engines (Avalara, TaxJar, ShipStation, EasyPost)
- Building a promotion/discount engine with rules, stacking, and abuse prevention
- Setting up abandoned cart recovery sequences (Klaviyo, Omnisend, or custom)
- Implementing BOPIS with real-time store inventory and pickup notifications

## Core principles
1. **Validate the cart on every read** — prices, stock, and promotions change; never trust a stale cart total
2. **Express checkout above the fold** — Apple Pay + Google Pay on product pages and cart converts before standard checkout even loads
3. **Guest checkout is not optional** — forced registration causes 10-25% abandonment; post-purchase signup instead
4. **Shipping rate circuit breaker** — always fall back to flat-rate if carrier APIs are down; never block checkout
5. **Recovery sequence timing matters** — T+1h (reminder), T+24h (urgency), T+72h (discount); discount-first burns margin

## Reference Files
- `references/cart-architecture.md` — storage strategies (session/DB/Redis/headless/hybrid), data model, cart merging, cart validation
- `references/express-checkout.md` — Apple Pay, Google Pay, Shop Pay, Amazon Pay integration patterns and best practices
- `references/checkout-flow-tax-shipping.md` — single-page vs. multi-step checkout, guest flow, address validation, shipping aggregators, tax engine integration
- `references/promotions-recovery-bopis.md` — promotion engine architecture, discount types, Klaviyo/Omnisend cart recovery, BOPIS flow and technical requirements


---
Source attribution: rnavarych
Original project: https://github.com/rnavarych/alpha-engineer/blob/c5b74102c7fd584af3d344ba7c331a7bbec3c729/plugins/domains/domain-ecommerce/skills/cart-checkout/SKILL.md
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Dave AI.

## Upstream license notice

MIT License

Copyright (c) 2026 Raman Navarych

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.



# Dave AI resource metadata

Creator / publisher: rnavarych
Original project: https://github.com/rnavarych/alpha-engineer/blob/c5b74102c7fd584af3d344ba7c331a7bbec3c729/plugins/domains/domain-ecommerce/skills/cart-checkout/SKILL.md
Attribution basis: Source repository record

Fields of work: Marketing, Sales
Roles: Business Development, Customer Success Manager, Growth Marketer, Product Marketer, Sales Operations
Specialties: Specialty not specified
Tools: Avalara, Easypost, Klaviyo, Omnisend, Shippo, Shipstation, Taxjar
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: 61083d3b7675b4b5f032f65a426d84db3324e02435db7daa358370e1821c0217