Platform channels

Multi-marketplace architectures with shared seller sign-up, multi-currency, and multi-language support.

This guide explains how platform channels group multiple marketplace channels under a single seller sign-up flow in SCX.

What you’ll learn:

• Why platform channels exist and what problem they solve
• How platform channels and marketplace channels relate to each other
• How the seller sign-up flow works from the seller’s and channel integrator’s perspective
• How you assign sellers to marketplace channels without additional sign-up sessions
• How stock sync groups prevent duplicate inventory updates

Why platform channels?

Some marketplaces operate across multiple geographic regions. Each region has its own language, currency, and regulatory requirements. For example, a marketplace may operate in Germany (EUR, German), the UK (GBP, English), and Spain (EUR, Spanish).

Without platform channels, each region would be a separate channel with its own sign-up flow. The seller would need to sign up multiple times — once for each region.

Platform channels solve this:

• One sign-up for the seller. The seller sees only the platform channel in JTL-Wawi and signs up once. Marketplace channels are invisible to the seller.
• Multi-currency support. Each marketplace channel defines its own currency.
• Multi-language support. Each marketplace channel represents a specific geographic region with its own language context.
• Centralized URL management. The sign-up and update URLs live on the platform and are inherited by all marketplace channels automatically.
• Automatic marketplace assignment. The channel integration creates or deactivates sellers on marketplace channels without requiring additional sign-up sessions from the seller.
• Shared inventory management. Stock sync groups prevent duplicate stock updates across marketplace channels that share the same warehouse.

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Terminology

Term	Definition
Platform channel	A virtual channel that acts as an umbrella for one or more marketplace channels. It owns the sign-up and update URLs and is the only channel visible to the seller in JTL-Wawi. It cannot be accessed via the Channel API. Example: “Amazon”.
Marketplace channel	A channel that belongs to a platform. It inherits URLs from its parent and represents a specific geographic marketplace. Invisible to the seller. Example: “Amazon DE”.
marketplaceChannelList	A property on the platform channel’s public channel list response. It contains identifiers and metadata (including stockSyncGroup) for each marketplace channel that belongs to the platform.
stockSyncGroup	A label grouping marketplace channels that share inventory. Within a group, JTL-Wawi sends stock updates to only one channel.

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Architecture

A platform channel is the entry point for seller sign-up. Each marketplace channel beneath it represents a specific region or variant.

Platform and marketplace channel relationship

Key characteristics:

• The platform channel holds the single source of truth for signUpUrl and updateUrl.
• When the platform’s URLs change, all marketplace channels are updated automatically.
• Marketplace channels cannot override their own URLs.
• Only the platform channel appears in the public channel list (GET /v1/public/channel). Marketplace channels are filtered out and invisible to the seller.

A platform channel is virtual. It cannot be accessed via the Channel API: no access token can be created for it, and it does not receive or emit events. It exists purely as an organizational umbrella that groups marketplace channels and owns the sign-up and update URLs.

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Seller sign-up flow

The seller sees only the platform channel in JTL-Wawi. They sign up once, and the channel integration handles marketplace channel assignment.

Platform seller sign-up flow

1. Seller initiates sign-up

   In JTL-Wawi, the seller selects the platform channel (e.g. “Amazon”) from the available channel list and starts a sign-up session. SCX returns the platform’s signUpUrl with a one-time session ID.

2. Seller authenticates on the channel

   The seller is redirected to the platform’s sign-up page (hosted by the channel integration). The channel integration authenticates the seller and determines which marketplace regions the seller should be connected to.

3. Channel completes platform sign-up

   The channel integration reports the seller ID and session ID back to SCX via POST /v1/channel/seller. This completes the platform-level sign-up.

4. Channel assigns seller to marketplace channels

   The channel integration calls POST /v1/channel/seller/platform/{jtlAccountId} to activate the seller on specific marketplace channels. No additional sign-up session is required.

Direct seller sign-up on a marketplace channel is not allowed. SCX rejects the request when a seller attempts to create a sign-up session for a marketplace channel (HTTP 403, error code SLR204). Sellers must always sign up via the parent platform.

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Managing sellers on marketplace channels

After the initial sign-up, the channel integration manages which marketplace channels a seller is active on. This happens without any seller interaction.

Creating a seller on a marketplace channel

Use POST /v1/channel/seller/platform/{jtlAccountId} to assign an existing platform seller to a marketplace channel. This endpoint requires Channel API authentication (Bearer token).

// POST /v1/channel/seller/platform/{jtlAccountId}
// Content-Type: application/json
// Authorization: Bearer <channel-access-token>
{
  "sellerId": "SELLER-123",
  "channel": "amazon-de",
  "isActive": true
}

The seller must already exist on the platform or on another marketplace channel of the same platform.

Deactivating a seller on a marketplace channel

The channel integration can deactivate a seller on a specific marketplace channel without affecting other marketplace channels or the platform-level connection:

// POST /v1/channel/seller/platform/{jtlAccountId}
{
  "sellerId": "SELLER-123",
  "channel": "amazon-de",
  "isActive": false
}

The channel integration decides which marketplace channels a seller is active on. SCX does not dictate marketplace channel assignment.

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URL inheritance

The platform channel owns the signUpUrl and updateUrl. All marketplace channels inherit these URLs automatically.

• When the platform’s URLs are updated, all marketplace channels receive the new URLs.
• Marketplace channels cannot set their own URLs independently.
• If no updateUrl is provided on the platform, the signUpUrl is used as fallback for both.

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Stock sync groups

Why stock sync groups?

Marketplaces that belong to the same platform often share inventory. For example, Amazon DE, Amazon FR, and Amazon ES all draw from the same European warehouse. The stock level is the same across all three marketplaces — the marketplace synchronizes inventory internally.

Without stock sync groups, JTL-Wawi would send a separate stock update to each marketplace channel. This creates unnecessary load and duplicate updates for stock that is already shared on the marketplace side.

How it works

A stockSyncGroup is a label assigned to marketplace channels that share inventory. Within a group, JTL-Wawi sends the stock update for a given SKU to only one marketplace channel. The marketplace handles internal synchronization across the other channels in the group.

Rules

• Only marketplace channels can have a stockSyncGroup (channels with a platform reference).
• Platform channels and standalone channels must have stockSyncGroup: null.
• All marketplace channels with the same stockSyncGroup value are treated as one inventory pool.
• The platform channel’s response in the public channel list (GET /v1/public/channel) includes the marketplaceChannelList property, which contains each marketplace channel’s stockSyncGroup. This is how JTL-Wawi discovers the grouping and sends stock accordingly.
• Setting stockSyncGroup to null removes the channel from its group — stock updates resume individually for that channel.

Example

Channel	Type	stockSyncGroup	Receives stock updates?
amazon	Platform	null	No (virtual channel)
amazon-de	Marketplace	"AMAZON-EU"	Yes (Wawi sends to one active seller in the group)
amazon-fr	Marketplace	"AMAZON-EU"	No (synced by marketplace)
amazon-es	Marketplace	"AMAZON-EU"	No (synced by marketplace)
amazon-us	Marketplace	"AMAZON-US"	Yes (separate group)

In this setup, Wawi sends one stock update per SKU to any single channel in the "AMAZON-EU" group (e.g. amazon-de). Amazon synchronizes stock across DE, FR, and ES internally. The US marketplace belongs to a separate group and receives its own stock updates.

Use the same stockSyncGroup value for all marketplace channels that share the same warehouse or inventory pool on the marketplace side. Use different values for regions with independent stock (e.g. EU vs US).

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Business rules and constraints

Rule
Platform channels are virtual — no API access token, no events, no authentication.
Seller sign-up on a marketplace channel is forbidden (SLR204). Sellers must sign up via the platform.
A platform cannot be converted to a regular channel while marketplaceChannelList is non-empty.
Marketplace channels cannot set their own sign-up or update URLs — always inherited from the platform.
A channel cannot be both a platform and belong to a platform simultaneously.
The referenced platform must exist when creating a marketplace channel.
stockSyncGroup can only be set on marketplace channels. Platform and standalone channels must have null.

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Next steps

Seller Management

Regular seller sign-up, update, and unlink flows.

Channel API Overview

Events, metadata, and media content handling.

Authorization

Refresh tokens, access tokens, and Bearer headers.

Channel API Reference

Full endpoint reference for the Channel API.