Using Webhooks and APIs to Keep Your Site and Marketplaces in Sync
How to Automate Product, Inventory, and Order Updates Across Channels in Real Time
Selling across multiple ecommerce platforms — your own website, Amazon, Walmart, eBay, TikTok Shop, and others — introduces one big technical challenge: keeping everything in sync.
That means syncing:
- Product listings
- Inventory levels
- Orders and fulfillment data
- Prices and promotions
To manage this efficiently and in real time, top-performing retailers use webhooks and APIs — the backbone of multichannel automation.
🧠 What Are Webhooks and APIs?
🔄 API (Application Programming Interface):
A set of defined rules and endpoints that allow software systems to communicate and exchange data.
You “ask” for information (e.g., inventory level), and the API “returns” it.
🚨 Webhook:
A real-time push notification sent when something changes — for example, when a product is purchased or a tracking number is updated.
Instead of polling constantly, the system is instantly alerted and can react accordingly.
Think of APIs as a conversation, and webhooks as alerts.
Together, they create a real-time automation layer between your store, marketplaces, apps, and warehouses.
🧩 What Needs to Stay in Sync?
| Function | Example Trigger | Solution |
|---|---|---|
| Inventory updates | Sale on Amazon reduces stock | Webhook triggers stock update across platforms |
| New product created | New listing on Shopify | API syncs to Amazon, Walmart, TikTok |
| Order placement | TikTok Shop sale occurs | Webhook sends order to your ERP/store |
| Shipping update | Order fulfilled | API sends tracking to all marketplaces |
| Price changes | Scheduled promo starts | Push updated pricing to all channels |
🛠 How It Works in Practice
Example: You sell a product on Amazon
- A webhook detects the order was placed
- Your ecommerce backend receives the notification
- Via API, it updates your inventory across:
- Shopify or WooCommerce
- Walmart Marketplace
- TikTok Shop
- At fulfillment, a tracking webhook is triggered
- A shipment update is sent to Amazon and other marketplaces via API
This happens in seconds, without manual work.
🔧 Connecting Your Site to Marketplaces with APIs & Webhooks
✅ Shopify
- Built-in API for products, inventory, orders, fulfillment
- Supports webhooks for real-time order, inventory, and customer events
- Easily integrates with tools like EcomBiz.AI, Zapier, or custom middleware
✅ WooCommerce
- REST API supports product, order, and inventory sync
- Webhook support requires configuration (e.g., via WP hooks or plugins)
- Commonly used with custom middleware or tools like WP Webhooks, EcomBiz.AI
✅ Amazon, Walmart, eBay, TikTok Shop
- Each offers their own developer API
- Authentication is required (OAuth or token-based)
- APIs can fetch:
- Inventory levels
- Listing statuses
- Orders
- Fulfillment and returns
Note: These APIs can be complex and rate-limited, requiring middleware or a multichannel tool for efficiency.
⚙️ Tools That Use APIs & Webhooks for Sync
| Tool | What It Does | Tech Under the Hood |
|---|---|---|
| EcomBiz.AI | Multichannel sync for listings, inventory, orders | Webhook + API-based automation |
| Zapier | Light automation between apps (Shopify, Gmail, Sheets) | Trigger-based via webhooks |
| Make (Integromat) | Custom multi-step flows for ecommerce events | API + webhook orchestration |
| ChannelEngine / Sellbrite | Centralized product and inventory feeds | API and feed-based syncing |
| Custom scripts / middleware | Full control for custom stacks | Developer-built API integrations |
🔐 Security and Reliability Considerations
- Always use secure HTTPS endpoints
- Authenticate using tokens, API keys, or OAuth
- Validate payloads and check signature headers to prevent spoofing
- Implement retry logic in case a webhook delivery fails
- Use logging and alerting to track sync failures in real time
🧭 Setting Up Webhook/API Sync: High-Level Workflow
- Connect Your Store’s API
(Shopify Admin API, WooCommerce REST API, etc.) - Configure Webhooks
Set triggers for product updates, order placement, fulfillment, etc. - Authorize Marketplace APIs
Get access tokens for Amazon, Walmart, eBay, TikTok, etc. - Map Product Identifiers
Align SKUs, GTINs, or custom IDs across platforms - Build or Deploy Middleware
Use a tool like EcomBiz.AI or a custom app to bridge platforms - Test All Syncs
Simulate inventory, order, and listing changes - Monitor, Log, and Scale
Set up error notifications, webhook replays, and sync logs
🧠 Pro Tip: Let EcomBiz.AI Handle the Tech for You
Instead of building your own webhook and API middleware, tools like EcomBiz.AI provide:
- Real-time syncing between your store and marketplaces
- AI-enhanced product listing generation for each channel
- Inventory, price, and order updates via robust webhook/API pipelines
- Smart routing of fulfillment and tracking across warehouses
This allows sellers to scale without hiring developers or losing control of multichannel workflows.
Final Thoughts: Syncing in Real Time Is No Longer Optional
Modern ecommerce requires your systems to be tightly connected. Delayed inventory updates, missing tracking numbers, or inconsistent listings aren’t just inconveniences — they’re lost revenue and risk.
Using webhooks and APIs lets your ecommerce platform act as a real-time command center, automatically syncing with all of your sales channels.
Whether you’re a Shopify seller launching on Walmart, or a WooCommerce merchant automating TikTok Shop listings, your tech stack should talk to each other instantly.