Slugifying a Path Without Breaking Its Structure

A URL slug is easy: one string in, one clean string out. A URL path is trickier, because it is not really one string — it is several strings stacked between slashes, and each of those segments means something different. Flatten a path with an ordinary slugifier and /Blog Posts/My Post/ becomes the unreadable blob blog-posts-my-post. Slugify it segment by segment and the structure survives: /blog-posts/my-post/. That difference is the entire point of path slugifying.

One recipe, applied per segment

The cleanup itself is the classic slug recipe described in How URL Slugs Work: lowercase everything, decompose accented letters and strip the accent marks, delete anything that is not a letter, digit, space, or hyphen, collapse runs of spaces and underscores into the separator, then trim separators off the ends. A path slugifier runs that exact pipeline once per segment rather than once per string. The segments are produced by splitting the input on slashes; the slashes themselves are never fed into the recipe.

input:  /Blog Posts/My Post/
split:  ['', 'Blog Posts', 'My Post', '']
slug:   ['', 'blog-posts', 'my-post', '']
join:   /blog-posts/my-post/

Notice the empty first and last segments — they are what the leading and trailing slashes are, and slugging an empty segment yields an empty segment. That is not a bug to guard against; it is the mechanism that keeps the shape of the path intact.

Why segment-by-segment matters

Run the same input through a plain slug generator and you get blog-posts-my-post: every slash becomes a separator, the hierarchy flattens into one label, and a two-level path can no longer be pasted into a router, a sitemap, or a permalink configuration. Segment-wise slugging keeps /a/b/c a three-level path. Each level gets its own independent cleanup, so punctuation and accents vanish at the segment level — Blog\2026\Café Notes! first has its Windows-style backslashes normalized to forward slashes, then comes out as blog/2026/cafe-notes.

The same independence is visible with awkward spacing. The input /a//b c/ splits into five segments — '', 'a', '', 'b c', '' — and rejoins as /a//b-c/. The double slash survives because an empty segment slugs to an empty segment, and the internal double space in b c collapses to a single separator within its segment only. Structure in, structure out.

Hyphens, underscores, and where they apply

Like any slug tool, a path slugifier lets you pick the word separator inside each segment. Hyphens are the conventional choice for URLs — search engines have historically read summer-sale-2024 as three words and summer_sale_2024 as one, and every framework defaults to hyphens. Underscores remain useful when the destination system demands them, which is common in file-oriented and legacy environments. Either way the separator lives inside a segment; slashes keep their job as the level divider. For a deeper comparison of naming conventions, see Camel Case vs Snake Case vs Kebab Case.

/Products/Summer Sale 2024/  with underscore separator
                          -> /products/summer_sale_2024/

Slugify Path vs the other slug tools

Three tools share one recipe but take different shapes of input. The Slug Generator handles a single string — one headline, one product name — and is the right choice when there is no path structure to preserve. The Slugify Batch tool takes many independent strings, one per line, for migrating an entire archive of titles. The Slugify Path tool is the one to reach for when the slashes mean something: nested routes, folder structures, category trees. Choosing wrong shows up immediately — a flattened path in the output is the symptom, and the fix is to switch to the segment-aware tool.

One practical boundary: the tool cleans characters, not semantics. It will not deduplicate a path, resolve .. segments, or enforce a maximum length. What it guarantees is that whatever structure you paste in comes out with the same number of levels and the same slashes in the same places.

Try it yourself

Paste /Blog Posts/My Post/ into the Slugify Path tool and compare it with the flattened output you would get from a plain slugifier — the slashes are the difference. Then try Blog\2026\Café Notes! to watch backslashes normalize and accents disappear, and switch the separator to an underscore to see /products/summer_sale_2024/ style output. When you have single strings rather than paths, the Slug Generator and Slugify Batch tools cover the rest of the family.