You can add BuiltWith to Gmail – currently there is no developer accessible app store for Gmail Add-ons but you can enable it using the Id below –

AKfycbwiCsbuUUXfiqcZ8fAHFNx8nPhVgLkxsPxgVoYrEGPe

  1. Open the Gmail add-on settings tab.
  2. In the Add-ons tab, ensure that you have selected the Enable developer add-ons for my account checkbox.
  3. Paste
    AKfycbwiCsbuUUXfiqcZ8fAHFNx8nPhVgLkxsPxgVoYrEGPe

    into the Install developer add-on textbox and click Install.

  4. In the Install developer add-on dialog that appears, click the checkbox to indicate that you trust this developer, then click Install.
  5. On a desktop device, open Gmail. You may need to refresh the tab if Gmail is already open.
  6. Choose a message in Gmail and open it.
  7. BuiltWith will appear as a column of icons to the right of the open email thread. Click on the bookmark icon that corresponds to the “Gmail Add-on Quickstart” you just installed.
  8. The add-on should place a contextual card on the right-side of the window, with a message asking for authorization. Click the Authorize access link to open a dialog where you can authorize the add-on.
  9. Select the account that should authorize the add-on.
  10. The next dialog may inform you that the app is not verified. In this case you can proceed by doing the following:
    1. Click Advanced.
    2. At the bottom of the dialog, click BuiltWith.
    3. In the new dialog, type “Continue” into the text field, then click Next.
  11. Read the notice in the next dialog carefully, then click Allow.
  12. Once authorized, the add-on should automatically refresh and start operating.