Amazon and Marketplace Seller Integrations

What a marketplace integration has to keep in sync

A brand selling on Amazon, Walmart Marketplace, eBay and its own store is running four storefronts against one warehouse. Each channel has its own product schema, its own order format, its own shipping deadlines and its own penalties when you miss them. Tepia starts these projects by tracing one SKU from the product record to every listing and back through an order, a shipment and a return, because that path shows where data gets retyped or lost today.

Inventory is the failure that hurts most. An oversold unit becomes a cancellation, cancellations damage account health metrics, and enough of them can suppress listings or put the account at risk. The integration has to treat the warehouse as the single source of available stock, hold back safety buffers per channel and update quantities quickly after every sale on any channel.

Fulfillment mode adds another layer. Units in Fulfillment by Amazon sit in Amazon’s network and must be tracked separately from units you ship yourself, and Walmart Fulfillment Services works the same way for Walmart orders. A good integration knows which pool each order draws from and tells your team when FBA stock needs replenishing. Returns follow the same split: an FBA return goes back into Amazon’s network, while a merchant fulfilled return has to be received, inspected and restocked in your warehouse before the quantity goes live again.

Channels, APIs and what to sync

Tepia builds against each marketplace’s official seller APIs and plans for the quirks every channel brings:

Tepia builds each connector as its own service behind a shared order and product model, so adding a channel later means adding a connector, not rewriting the warehouse integration. Amazon rate limits are handled with queues and backoff rather than hammering the API during Prime Day or a holiday peak. Every sync failure lands in a dashboard with the SKU, the channel and the error, so your team fixes the cause instead of guessing.

Connecting marketplaces to your ERP and warehouse

The marketplace side is only half the work. Orders need to land in the system that picks, packs and accounts for them. Tepia typically connects:

• NetSuite or another ERP for sales orders, item records and settlement reconciliation by channel; see our NetSuite integration page.
• Warehouse management systems or 3PL portals for pick and ship, with shipment confirmations flowing back to each marketplace.
• Shipping label services such as ShipStation or direct carrier APIs, so tracking numbers post the moment a label prints.
• QuickBooks for smaller sellers who reconcile settlement reports by channel each period.
• Product information management tools or a custom product record holding the master copy of titles, images and attributes.

Settlement reports deserve care. Each marketplace pays out on its own schedule with deductions for referrals, fulfillment, returns and advertising, and Tepia parses those reports into journal entries by channel so finance sees each channel’s true contribution instead of one lump deposit. For keeping your own web store aligned, see ecommerce inventory sync and ERP integration.

How Tepia approaches marketplace seller integrations

Tepia runs its six phase process for marketplace work, with a US based project manager who also handles developer registrations and approvals with each channel.

1. Discovery: a review of seller accounts, current tools and spreadsheets, interviews with marketplace managers, warehouse leads and finance, and a check of API access for each channel. Deliverables are an Investigation Summary, an Interview Summary and User Stories such as a warehouse lead seeing an Amazon order ready to pick within minutes.
2. Design: integration architecture, an attribute mapping spec per channel, and wireframes for the operations dashboard where staff see sync errors, stuck orders and low stock.
3. Development and Testing: an Alpha against marketplace sandboxes and a Beta with a subset of SKUs live, with test plans for oversell prevention, order accuracy, throttling and acceptance by the marketplace team.
4. Training: sessions for marketplace managers and warehouse staff on resolving listing errors and handling exceptions.
5. Launch: a channel by channel cutover from the old connector or spreadsheet process, migration of SKU mappings and Tepia support reps watching account health metrics.
6. Support: monitoring, bug tracking and updates as marketplaces change APIs or category rules.

Typically Discovery runs 1 to 3 months, development and QA 2 to 6 months and cutover about a month, sequenced so your highest volume channel moves first. See our process.

Multichannel tools or a custom integration

Off the shelf multichannel listing and inventory tools work well for many sellers, especially those with a few hundred SKUs, standard fulfillment and one warehouse. Tepia will point you there when it fits.

A custom integration earns its keep when:

• You run thousands of SKUs with variants, bundles or kits that the tool cannot model.
• Your ERP or warehouse has custom logic the connector ignores.
• You split stock across FBA, your own warehouse and a 3PL and need channel level allocation rules.
• You want account health, buy box share and channel margins in one dashboard.

If you are building your own marketplace rather than selling on others, that is a different project; compare options in Sharetribe vs a custom marketplace build. Otherwise, browse our work or talk with Tepia about your channels.

Frequently asked questions