How to Find Your AvantLink Merchant ID and API Key

October 5, 2026 · 5 min read

Short answer:

Merchant ID: sign in to AvantLink. It's in the upper right corner of the dashboard, and under Account Settings → Account Information.

API key: it isn't on any settings page, but you can pull it yourself. Run any report, open Show Report Subscription Options, and click XML. The link that opens contains auth_key=. The value after it is your key. If that doesn't work for your login, email support@avantlink.com and ask for it.

Any tool that reads your AvantLink sales and click data needs two values: your Merchant ID and an API key. AvantLink's API calls the key auth_key. Some tools label it Secret Key or Authentication Key. They all mean the same thing.

The Merchant ID takes ten seconds to find. The key is where people get stuck, because no settings page displays it. It does appear in the link AvantLink generates for report subscriptions, which is the fastest way to get it.

Step 1: Find your Merchant ID

  1. Sign in to your AvantLink merchant account.
  2. Look in the upper right corner of the dashboard. The number shown there is your Merchant ID.
  3. If you don't see it, open the menu and go to Account Settings → Account Information.

The Merchant ID is a number. It identifies your program, not your login, so everyone on your team sees the same one.

Step 2: Copy the API key from a report subscription link

  1. In AvantLink, go to Reports and click Show Report Form.
  2. Pick your program in the Merchant Program dropdown and choose Performance Summary as the report.
  3. Click Select Report and let it load.
  4. Click Show Report Subscription Options, then XML.
  5. A page of XML opens. Look at its address. It reads like classic.avantlink.com/api.php?module=MerchantReport&auth_key=…&merchant_id=…
  6. Copy the characters between auth_key= and the next &. That's your API key. The number after merchant_id= is your Merchant ID, which is a good check that you're in the right account.

Treat that link like a password. Anyone with the full URL can read your program's sales and commissions. Don't paste it into shared docs, tickets or chat threads. Store the key in a password manager.

If the subscription link doesn't show a key

Ask AvantLink support for it. Send the request from an email address that is a user on the merchant account, so support can match it to your program. Here's an email you can copy:

To: support@avantlink.com

Subject: Merchant API key request, Merchant ID [your ID]

Hi, please issue a merchant API authentication key for our account, Merchant ID [your ID]. We're connecting a reporting tool that reads our transaction, click and affiliate data. Thanks, [name, company]

If a key has been shared somewhere it shouldn't be, ask support to reissue it. The old one stops working, so update any tools that use it.

AvantLink Canada is a separate account

If you run a Canadian program, it lives on AvantLink's Canadian platform at classic.avantlink.ca. It has its own Merchant ID and its own API key. Your US key will not return Canadian data, and the Canadian key will not return US data.

Repeat both steps while signed in at classic.avantlink.ca. The subscription link there starts with classic.avantlink.ca and carries the Canadian key. If you email support instead, say the key is for your Canadian program.

Canadian sales report in CAD. If you combine the two programs anywhere, convert CAD to USD at each day's rate rather than adding the numbers together.

Common problems

What you seeLikely cause
Invalid authentication or empty resultsThe key and Merchant ID are from different accounts, often a US key paired with a Canadian Merchant ID or the reverse.
Key rejected right after pastingA space or line break came along with the copied key. Paste it into a plain text editor first and copy it again.
Key copied from the link doesn't workExtra characters came along. The key ends right before the next & in the URL.
Support asks you to verify the accountThe request came from an address that isn't a user on the merchant account. Resend from an admin login.
You only have an affiliate (publisher) keyPublisher API keys belong to a website, not a merchant program. Merchants need a merchant key.

Connecting AvantLink to OptimizeAffiliate

In the OptimizeAffiliate Shopify app, open Settings, expand AvantLink, paste the Merchant ID and API key, and click Save & Validate AvantLink. The app checks the credentials and starts the first sync of your transactions, clicks and approved affiliates.

For a Canadian program, use AvantLink CA under More networks in Settings with the Canadian Merchant ID and key. Brands on both see each program on its own and a combined total, with CAD converted to USD at the European Central Bank rate for each sale's date. See the Settings docs for the full setup.