Installing SEO Merlin

Before you start

There are only two hard requirements, and most modern sites already meet them: WordPress 6.5 or newer and PHP 8.1 or newer. If you’re not sure what you’re running, your host can tell you in a few clicks, or look under Tools → Site Health in your dashboard.

You also need to be an administrator on the site. SEO Merlin makes changes to your content, and only admins are allowed to do that.

One thing you don’t need yet: an AI key. The plugin scans your whole site and shows every problem without one. You add a Claude key later, only when you want it to write the fixes for you — that’s covered in its own guide.

Installing the plugin

1. Upload it. In your dashboard, go to Plugins → Add New → Upload Plugin. Choose the SEO Merlin ZIP file you downloaded and click Install Now. If you’d rather, you can drop the plugin folder straight into wp-content/plugins using your file manager or FTP.
2. Activate it. Once installing finishes, click Activate. That’s the moment the plugin comes to life on your site.
3. Find it in the menu. Look at the left-hand sidebar. A new item called SEO Merlin appears with a magnifying-glass icon. Click it to open the app.

What happens next

The first time you open SEO Merlin, a setup wizard starts on its own to walk you through the basics. You can follow it or skip it entirely, and it picks up where you left off if you close it partway through.

After that first run, opening SEO Merlin always takes you straight to your Dashboard. The whole thing lives inside your WordPress admin — there’s no separate website to visit and nothing to log into twice.

If something goes wrong

Two things account for almost every failed install:

• “The plugin does not have a valid header” — you’ve most likely uploaded the wrong ZIP, or unzipped it first. Upload the original file exactly as you downloaded it.
• A fatal error on activation — nearly always PHP below 8.1. Check Tools → Site Health, and ask your host to bump the PHP version. It’s usually a one-click change in their control panel.

Anything else, write in with the exact error text and a real person will look at it.

Next: The setup wizard →