A trailing slash is a forward slash at the end of a URL's path, as in /pricing/ rather than /pricing. To search engines, the two forms are separate URLs that can return different content or duplicates of the same page. Neither form is better for SEO; what matters is choosing one, serving content only on that version, and redirecting the other.
Why it matters
If both versions return a 200, crawlers find two copies of each page and must pick a canonical. Internal links and backlinks may be split between them. The exception is the bare domain: https://example.com and https://example.com/ are treated as the same URL, because a path cannot be empty.
Setting a convention
Pick a format and enforce it at the framework or server level, with a single 301 or 308 redirect from the other form. Then make every internal link, canonical tag, hreflang entry and sitemap URL use the chosen form, so crawlers rarely hit the redirect.
// next.config.js: serve URLs without a trailing slash (the default)
module.exports = { trailingSlash: false };
// or force a trailing slash on every path
module.exports = { trailingSlash: true };Where mismatches come from
Problems usually appear when two systems meet: a blog on one CMS that adds slashes and a marketing site on a framework that strips them, or a reverse proxy that rewrites paths. Migrations are the other common source, when the new platform has a different default from the old one.
Example
Two platforms, two conventions
Saltmarsh, a field service SaaS, serves its marketing site from a framework that omits slashes and proxies /blog/ to a hosted CMS that adds them. Crawls show blog links pointing to /blog/post-name, which redirects to /blog/post-name/. The team updates the CMS link templates and the main site's nav so every link matches the final URL.
Common mistakes
Serving 200 on both versions
Even with a canonical tag, two live versions invite duplicate URLs and split links. Redirect one.
Canonical tags that disagree with the redirect
If /page redirects to /page/ but the canonical points to /page, you send Google conflicting signals.
Questions
Only with a good reason, such as a migration. Changing it means redirecting every URL, which carries the usual migration risk for no ranking benefit.
