Blog — Guides

Guides for building on the Zinc API

Tutorials and deep dives on APIs, agentic commerce, and retailer integrations.

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35 Guides posts

Scale Dropshipping Without Hiring (2026)

Guides

8/31/2026

Scale Dropshipping Without Hiring (2026)

Scale dropshipping by automating supplier orders with a purchasing API instead of hiring more people to click checkout.

How to Automate Secret Santa: Match, Buy & Ship (2026)

Guides

8/29/2026

How to Automate Secret Santa: Match, Buy & Ship (2026)

Elfster handles matching. Learn how to automate Secret Santa buying and shipping with a purchasing API from draw to delivery.

How to Automate New Hire Welcome Gifts (2026)

Guides

8/28/2026

How to Automate New Hire Welcome Gifts (2026)

Trigger welcome kits from your HRIS, collect an address, buy the gift, and track delivery. Follow this step-by-step guide.

How to Automate Employee Rewards Fulfillment (2026)

Guides

8/26/2026

How to Automate Employee Rewards Fulfillment (2026)

Points platforms stop at catalogs. Learn how to automate physical employee rewards with HRIS triggers and a purchasing API.

Guides

8/24/2026

How to Send Donuts or Postcards via API

Postcard APIs print mail. Food APIs order delivery. A purchasing API buys donuts, gifts, and retail items and ships them.

How to Build an AI Gift Finder That Actually Buys (2026)

Guides

8/22/2026

How to Build an AI Gift Finder That Actually Buys (2026)

AI gift finders suggest ideas but rarely checkout. Learn how to connect recommendations to a purchasing API so gifts ship.

Programmatic Returns API: How to Handle Refunds (2026)

Guides

8/21/2026

Programmatic Returns API: How to Handle Refunds (2026)

Automate returns in code instead of support tickets. Compare Zinc, Loop, Rye, and OpenReturn, then wire retailer-side refunds.

How to Build an Amazon Price Tracker That Auto-Buys (2026)

Guides

8/19/2026

How to Build an Amazon Price Tracker That Auto-Buys (2026)

Keepa alerts you when prices drop. Learn how to add auto-buy with a purchasing API, max_price caps, and idempotency keys.

Price & Stock Comparison API: Compare and Buy (2026)

Guides

8/17/2026

Price & Stock Comparison API: Compare and Buy (2026)

Data APIs return offers. Learn how to compare live prices and stock across retailers, then buy the winning SKU in one flow.

Order Fulfillment vs Purchasing API: Which to Use (2026)

Guides

8/15/2026

Order Fulfillment vs Purchasing API: Which to Use (2026)

ShipBob ships inventory you own. Zinc buys from retailers. Learn which API fits marketplace fulfillment vs purchasing.

How to Automate Orders Across Ecommerce Sites (2026)

Guides

8/14/2026

How to Automate Orders Across Ecommerce Sites (2026)

Stop logging into every retailer. Learn how to place buy-side orders across Amazon, Walmart, Target, and 50+ sites with one API.

How to Buy from Amazon, Walmart & Target via API (2026)

Guides

8/12/2026

How to Buy from Amazon, Walmart & Target via API (2026)

Official retailer APIs cannot place shopper orders. Learn how one purchasing API checks out at Amazon, Walmart, and Target.

Universal Checkout: Payments vs Buying (2026)

Guides

8/10/2026

Universal Checkout: Payments vs Buying (2026)

Universal checkout can mean payments or retailer buying. Learn which API you need and how Zinc differs from Primer and UCP.

AI Agent Checkout API: How to Pick ACP vs Retail (2026)

Guides

8/8/2026

AI Agent Checkout API: How to Pick ACP vs Retail (2026)

Learn which checkout API lets your AI agent buy at Amazon and Walmart, not just ACP merchants in ChatGPT. Read this guide.

Can AI Buy Things Online? What Works in 2026

Guides

8/7/2026

Can AI Buy Things Online? What Works in 2026

Yes, with limits. Learn what ChatGPT Instant Checkout covers, what it cannot buy, and how a purchasing API closes the gap.

Guides

8/5/2026

What Is an AI Shopping Agent?

An AI shopping agent finds products and completes checkout. Learn how it works and how to build one that actually buys.

Guides

8/4/2026

10 AI Shopping Prompts for Zinc API

Copy 10 Zinc API agent prompts to search retailers, place orders with max price caps, and track delivery. Includes hands-free checkout with Universal Checkout.

How to Automate Corporate Gifting With an API

Guides

8/4/2026

How to Automate Corporate Gifting With an API

Compare corporate gifting APIs and learn how to automate physical gifts, address collection, ordering, spend controls, tracking, and delivery.

Agentic Commerce in 2026: Where We Stand & What's Next

Guides

7/23/2026

Agentic Commerce in 2026: Where We Stand & What's Next

AI agents are buying products for humans now. Learn the state of agentic commerce in 2026 and get 5 steps to optimize your online store for machine buyers.

How to Buy Products Online with AI: APIs, Agents & MCP (2026)

Guides

7/16/2026

How to Buy Products Online with AI: APIs, Agents & MCP (2026)

Learn how AI agents buy physical products online — from ChatGPT-style prompts to purchasing APIs, MCP skills, and production checkout with Zinc.

Best MCP Servers for Retail & Online Shopping (2026)

Guides

7/15/2026

Best MCP Servers for Retail & Online Shopping (2026)

Compare MCP servers that help AI agents search products, place orders, and manage retail workflows — including Zinc Universal Checkout, Shopify, and open-source options.

Shipment Tracking API for Developers: Polling, Webhooks, and Multi-Retailer Tracking (2026)

Guides

7/8/2026

Shipment Tracking API for Developers: Polling, Webhooks, and Multi-Retailer Tracking (2026)

Developer guide to shipment tracking APIs: poll orders, handle webhooks, normalize checkpoints, and track shipments across Amazon, Walmart, and 50+ retailers with Zinc.

7 Best Ecommerce Purchasing APIs for Developers (2026)

Guides

7/7/2026

7 Best Ecommerce Purchasing APIs for Developers (2026)

Looking for an ecommerce API that actually places orders? Compare 7 purchasing APIs and pick the right stack for your app.

10 Best Returns Management Software for Ecommerce (2026)

Guides

7/7/2026

10 Best Returns Management Software for Ecommerce (2026)

Compare 10 returns management platforms for ecommerce in 2026. Loop, Narvar, ReturnGO, AfterShip, and more ranked by API depth and use case. See the list.

Procurement Automation API: Build Internal Buying Workflows

Guides

7/7/2026

Procurement Automation API: Build Internal Buying Workflows

Learn how a procurement automation API automates retail order placement when platforms like Spendflo and Zapier stop at checkout. Build your workflow.

Web Scraping vs Ecommerce API: Data and Buying (2026)

Guides

7/7/2026

Web Scraping vs Ecommerce API: Data and Buying (2026)

Compare web scraping vs ecommerce APIs for product data, checkout, and order tracking. Learn when scraping fits and when you need a purchasing API.

How to Build an AI Shopping Agent: Step-by-Step Guide

Guides

4/16/2026

How to Build an AI Shopping Agent: Step-by-Step Guide

Build an AI shopping agent that actually completes purchases, not just suggests them. Full walkthrough with Claude, MCP tools, Zinc for order execution, and MPP for payments.

What Is HTTP 402 Payment Required? A Complete Guide

Guides

4/16/2026

What Is HTTP 402 Payment Required? A Complete Guide

HTTP 402 was reserved in 1997 and unused for 30 years. Here's the history, the current revival via x402 and MPP, and why it's becoming the foundation of agentic commerce.

MPP vs x402: Which Agent Payment Protocol to Use?

Guides

4/16/2026

MPP vs x402: Which Agent Payment Protocol to Use?

MPP (Stripe + Tempo) and x402 (Coinbase) both revive HTTP 402 for agent payments. Here is a technical comparison and when to use each, with code.

What Is ACP? The Agentic Commerce Protocol Explained

Guides

4/16/2026

What Is ACP? The Agentic Commerce Protocol Explained

ACP is the open protocol for agent-to-merchant checkout from Stripe and OpenAI. Here's how it works, its four endpoints, Shared Payment Tokens, and what it can't do.

What Is AP2? The Agent Payments Protocol Explained

Guides

4/16/2026

What Is AP2? The Agent Payments Protocol Explained

AP2 is Google's open protocol for authorizing AI agent payments with cryptographically signed mandates. Here's how it works, its three mandate types, and when to use it.

What Is MPP? A Developer's Guide to Machine Payments

Guides

4/16/2026

What Is MPP? A Developer's Guide to Machine Payments

MPP lets AI agents pay for anything over HTTP without an account. Here's how the Machine Payments Protocol actually works, how it compares to x402 and ACP, and real production code.

Amazon Shopping API: How to Buy Programmatically (2026)

Guides

3/16/2026

Amazon Shopping API: How to Buy Programmatically (2026)

Amazon has no public buy API. Compare SP-API, PA-API, and Buy with Prime, then learn how developers place orders in code.

Walmart Shopping API: The Ultimate Guide to Programmatic Buying (2026)

Guides

3/16/2026

Walmart Shopping API: The Ultimate Guide to Programmatic Buying (2026)

Everything you need to know about Walmart APIs, their limitations for developers, and how to use Zinc as a complete Walmart Shopping API.

Multi-Product Ordering API: Order Multiple SKUs Across Retailers at Scale

Guides

1/19/2026

Multi-Product Ordering API: Order Multiple SKUs Across Retailers at Scale

Order multiple products with quantities in a single API request. Multi-SKU checkout across Amazon, Walmart, Target, and 50+ retailers with Zinc.