Your CartOS store doesn't have to be the only place you sell. With the Stock Genius bolt, you can list products and manage inventory across dozens of marketplaces and platforms—all from your CartOS admin.
What is Stock Genius?
Stock Genius is a core bolt that turns CartOS into your central hub for multi-channel selling. Connect your accounts on Amazon, eBay, Etsy, Walmart, and many other platforms, then manage everything from one place: listings, inventory, orders, and pricing.
The key benefit is unified inventory. When something sells on any channel, Stock Genius updates your inventory everywhere in real-time. No more overselling because your eBay listing didn't know about your Amazon sale.
Supported platforms
Stock Genius connects to a wide range of marketplaces and selling platforms:
Major marketplaces
- Amazon – US, Canada, Mexico, UK, EU, Australia, Japan
- eBay – All major eBay sites worldwide
- Walmart Marketplace
- Etsy
- Target Plus
- Newegg
- Wish
Social commerce
- Facebook Shop and Instagram Shopping
- TikTok Shop
Comparison shopping
- Google Shopping
- Bing Shopping
- PriceGrabber
Specialty marketplaces
- Reverb – Musical instruments
- Poshmark – Fashion resale
- Mercari
- Bonanza
- Ruby Lane – Antiques and collectibles
- Chairish – Furniture and decor
International
- Rakuten – Japan
- Cdiscount – France
- Allegro – Poland
- Bol.com – Netherlands, Belgium
- Fruugo – Multi-country
New channels are added regularly. If there's a platform you need that isn't listed, let us know—we may already be working on it.
Installing Stock Genius
Go to Bolts in your admin and find Stock Genius. Click Install to add it to your store. Once installed, you'll see a new Channels section in your sidebar.
Stock Genius is included with your CartOS subscription at no additional cost for the core functionality. Some advanced features or high-volume usage may have additional pricing—check the bolt details for specifics.
Connecting a channel
Go to Channels › Add Channel and select the platform you want to connect. Each channel has its own connection process:
Most channels use OAuth—you'll be redirected to log in to your account on that platform and authorize CartOS to access it. Once authorized, you're connected and can start listing.
Some channels require API credentials that you'll need to generate in your seller account on that platform. Stock Genius provides step-by-step instructions for each channel's specific requirements.
Inventory sync
This is where Stock Genius shines. Once connected, your inventory stays synchronized across all channels automatically.
How it works
When you connect a channel, Stock Genius imports existing listings and matches them to your CartOS products (by SKU, UPC, or manually). From that point on, inventory quantities sync continuously.
Sell one unit on Amazon? Your eBay, Etsy, and CartOS quantities all update within minutes. Get a return on your website? Inventory goes back up everywhere. The sync runs constantly, not on a schedule, so you're always current.
Buffer stock
You can set a buffer quantity per channel if you want to hold back some inventory. For example, if you have 10 units but set a buffer of 2 for Amazon, Amazon will show 8 available. This is useful for reserving stock for specific channels or avoiding overselling during sync delays.
Channel-specific inventory
Some merchants want to allocate inventory to specific channels rather than sharing a single pool. Stock Genius supports this too—you can assign quantities per channel instead of using unified inventory.
Listing products
You have two approaches for getting products listed on channels:
Push from CartOS
Select products in your CartOS catalog and push them to connected channels. Stock Genius creates listings using your product data—title, description, images, price, variants. You can customize the listing details per channel before publishing.
Link existing listings
If you already have listings on a marketplace, Stock Genius can import and link them to your CartOS products. This connects inventory sync without recreating listings from scratch.
Listing optimization
Different channels have different requirements and best practices. Amazon wants bullet points and backend keywords. eBay has item specifics. Etsy favors certain tags. Stock Genius lets you customize your listings per channel while maintaining a single source of truth in CartOS.
Order management
Orders from all channels flow into your CartOS admin. You'll see them in Orders with a channel indicator showing where each order originated.
Fulfill orders the same way you handle CartOS orders—through the Fulfillment Bolt or manually. When you mark an order as shipped and add tracking, Stock Genius pushes that information back to the originating channel so the customer sees updates there.
This unified order management means one workflow regardless of where the sale came from. Your team doesn't need to log into five different seller portals to ship orders.
Pricing across channels
You can set channel-specific pricing if needed. Marketplaces have different fee structures, and you may want to adjust prices to maintain margins.
Options include using your CartOS price everywhere, setting a fixed price per channel, or applying a rule (like "Amazon price = CartOS price + 10%"). Stock Genius keeps prices updated automatically when your base price changes.
Channel fees and requirements
Each marketplace has its own seller fees, policies, and requirements. Stock Genius helps you sell on these platforms, but you're still bound by each platform's terms of service.
Common considerations include referral fees (percentage of sale), monthly subscription fees for professional seller accounts, category-specific requirements or restrictions, and shipping/fulfillment expectations (especially for Amazon Prime or Walmart TwoDay).
Research each channel's fee structure and policies before connecting. The margin math can vary significantly between platforms.
Reporting
Track performance across channels in Quick Actions › Reports. The Sales by Channel report shows revenue, orders, and units sold broken down by channel. Compare which platforms are driving the most business and which have the best margins after fees.
You can also see channel-specific metrics like listing health scores (for Amazon), seller ratings, and sync status from the Channels dashboard.
Common multi-channel strategies
Marketplace discovery, website conversion
Use marketplaces to reach new customers, then include inserts or follow-up that encourages them to buy directly from your website next time. Direct sales mean better margins and customer relationships.
Channel-specific products
Some products perform better on certain channels. Handmade items thrive on Etsy. Electronics do well on Amazon and Newegg. Use Stock Genius to tailor your catalog to each platform's audience.
Liquidation channel
Use eBay or discount marketplaces to move slow inventory while keeping your primary channels fresh with current products.
Getting help
Multi-channel selling adds complexity. If you're new to a particular marketplace or running into issues with Stock Genius, our support team can help. We've assisted merchants selling on dozens of platforms and can share what works.