# Trailing slash consistency

> Trailing slash consistency means every URL is used in one form only, either /page or /page/, and the other form redirects to it.

- **Check ID:** S23
- **Area:** [SEO](https://be1st.ai/glossary/seo)
- **Tool:** [SEO + Security + Performance](https://be1st.ai/tools/ssp-audit)
- **Page:** https://be1st.ai/glossary/seo/trailing-slash-consistency

## Why it matters

Inconsistent use of trailing slashes creates duplicate URLs, which confuses search engines and splits link equity. The site should use one convention and redirect the other.

## In practice

Next.js allows setting trailingSlash: true/false in its configuration. Apache servers often add trailing slashes automatically for directories. It is important to have a consistent rule and a 301 redirect for the alternate variant.

## How be1st checks it

Checks for consistent use of trailing slashes in URLs. The addresses /page and /page/ are different URLs for search engines and should be unified. The check compares the trailing slash in the page address and in its canonical URL.

[SEO + Security + Performance](https://be1st.ai/tools/ssp-audit), SEO tab.

Every check ends as: Pass, Warning, Fail.

## Sources

- [Consolidate Duplicate URLs](https://developers.google.com/search/docs/crawling-indexing/consolidate-duplicate-urls) (Google Search Central)
- [Google Search Essentials](https://developers.google.com/search/docs/essentials) (Google Search Central)

## Related terms

- [Canonical URL](https://be1st.ai/glossary/seo/canonical-url): A canonical URL is the preferred address of a page, set with `<link rel='canonical'>`. It tells search engines which version to index when the same content has several URLs.
- [HTML size (SEO)](https://be1st.ai/glossary/seo/html-size): HTML size is the weight of a page's HTML document in kilobytes, without images, styles and scripts. Search engines and browsers have to download and parse all of it.
- [Mobile-friendly indicators](https://be1st.ai/glossary/seo/mobile-friendly-indicators): Mobile-friendly indicators are the signs that a page adapts to small screens: a viewport tag, responsive CSS and content that fits without zooming.
- [Content length](https://be1st.ai/glossary/seo/content-length): Content length is the number of words of visible text on a page. A page with too little text rarely answers a question well enough to rank.
- [Keyword density](https://be1st.ai/glossary/seo/keyword-density): Keyword density describes how often the words a page targets appear in its text. Here it means whether the words from the title also show up in the content.
- [Hreflang tags](https://be1st.ai/glossary/seo/hreflang-tags): Hreflang tags tell search engines which language or regional version of a page to show to which users on a multilingual website.