> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hadoseo.com/llms.txt
> Use this file to discover all available pages before exploring further.

# GSC Shows "Not Indexed - Duplicate URL"

> Fix duplicate URL issues reported by Google Search Console

Google Search Console may report pages as duplicates when it finds multiple URLs with the same content.

## What Are Canonical URLs?

A canonical URL tells Google which version of a page is the "official" one. Without this, Google may see duplicates:

* `https://example.com/about`
* `https://example.com/about/`
* `https://www.example.com/about`
* `https://example.com/about?ref=twitter`

## Common Causes

| Issue            | Example                                       |
| ---------------- | --------------------------------------------- |
| www vs non-www   | `example.com` and `www.example.com` both work |
| Trailing slashes | `/about` and `/about/` both work              |
| Query parameters | `/page` and `/page?utm_source=x`              |
| HTTP vs HTTPS    | Both protocols accessible                     |

## How to Fix

**1. Add canonical tags to every page:**

```html theme={null}
<link rel="canonical" href="https://yourdomain.com/about" />
```

In React with Helmet:

```jsx theme={null}
<Helmet>
  <link rel="canonical" href={`https://yourdomain.com${location.pathname}`} />
</Helmet>
```

**2. Set up redirects for duplicates:**

Choose one canonical format and redirect others:

* Pick either `www` or non-www (non-www is simpler)
* Pick either trailing slash or no trailing slash
* Redirect HTTP to HTTPS

**3. Be consistent with internal links:**

Always link to the canonical version of URLs in your navigation and content.

<Info>
  All Hado SEO plans include routing rules with redirect support. Starter plans include up to 5 rules; all other plans include unlimited rules. Configure these in your [Routing Rules](/dashboard/routing-rules) to automatically redirect duplicates.
</Info>