This is a candidate setup guide for accounts where MerchOne is explicitly shown as available in Integrations → Fulfillment. Only the live Integrations screen for your account is authoritative; this article, a provider logo, or a direct URL does not prove availability. If MerchOne is absent or unavailable there, stop: it is outside your current live scope.
When the MerchOne setup action is enabled, use this guide to enter the credentials shown on that page. A healthy connection can let you configure an eligible product mapping, but it is not proof of fulfillment readiness: test the complete order handoff and confirm an accepted provider reference before production.
For a wider look at how providers work in Composerie, see connect a provider.
Before you start
Connecting MerchOne takes two values: a Store User and a Store API Key. Both come from your MerchOne account, so have it open in another tab.
Here is what to gather first:
- A MerchOne account with access to its store settings. If you do not have one yet, create it at the MerchOne dashboard.
- Your Store User and Store API Key. You will find these in the API credentials section of your MerchOne store settings.
The Composerie connect page makes this easier. It links straight to the MerchOne dashboard and to the MerchOne API docs, and it includes a short setup guide titled “How to set up MerchOne”. That guide walks through signing in, finding the API credentials, and pasting them into Composerie.
Enter your MerchOne credentials
If the available MerchOne setup page requests both values, enter them there, test the connection, and then connect.
Open the MerchOne connect page
In the Composerie dashboard, go to Integrations, then the Fulfillment section. Continue only when the MerchOne card explicitly shows an available setup action, then select it to open the connect page.
Enter your Store User
In the first field, labeled Store User, paste the Store User value from your MerchOne API credentials. This is a plain field, so the text stays visible as you type.
Enter your Store API Key
In the second field, labeled Store API Key, paste your API key. Composerie treats this field as sensitive, so it is masked as you type. Use the show or hide control if you want to confirm what you pasted.
Test the connection, then connect
Select Test connection. Composerie makes a live call to MerchOne with both values to confirm they are valid. If the test passes, you can finish by selecting Connect. If it fails, the page tells you what went wrong so you can fix the value and try again.
Once the connection is saved, the page switches to its connected view. You will see a Last verified time, which tells you when Composerie last confirmed the credentials still work, and a Browse Catalog button to start adding MerchOne products.
Troubleshooting
If the test does not pass, the problem is almost always one of the two values. Work through these first.
The test connection keeps failing. What should I check?
Recheck both values for stray spaces or missing characters. The Store User goes in the first field and the Store API Key goes in the masked field. It is easy to swap them by accident.
Where do I find my Store User and Store API Key?
Both live in the API credentials section of your MerchOne store settings. The setup guide on the connect page links straight to the MerchOne dashboard and API docs.
My Store API Key field shows dots instead of the key. Is that a problem?
No. That field is masked on purpose because the key is sensitive. Use the show control to confirm the value, then hide it again.
How do I know the connection is still working later?
Open the MerchOne page anytime and look at the Last verified time. To keep a connection healthy over time, see the keep a provider connection healthy guide.
If you are still stuck after checking both values, contact support and we will help you connect.
Next
After the connection, mapping, and end-to-end test are verified, use browse a provider catalog to continue with an eligible MerchOne product. Do not treat a connected badge by itself as production readiness.