Does Safe Filename upload my file or text to Tool-You servers?

No. Safe Filename runs in this browser tab. Files stay on the device. Limit note: Windows-illegal characters. Optional length cap 1–255. Empty, . and .. fail.

Should I use Slugify instead of Safe Filename?

Use Safe Filename when you need Replace illegal filename characters; length, case, spaces. Use Slugify when you need Turn text into a URL slug with separator and length options. They share a category (Developer) but not the same job.

Safe Filename

Replace illegal filename characters; length, case, spaces.

Replaces < > : " / \ | ? * and controls. Optional replacement character, max length, lowercase, and space replacement. Unlike Slugify this can keep case and spaces. Unlike CSS Identifier Escape this is a filename, not a CSS ident. Empty names and . or .. fail.

What Safe Filename does

The interactive controls for Safe Filename load after this article so crawlers still read the instructions. Path /developer/filename-safe is the canonical address. Work happens on this device; Tool-You does not take a copy of the file or pasted text for Safe Filename.

How to use Safe Filename

Keep this tab on Safe Filename (/developer/filename-safe). Pasting into the wrong Developer tool (for example Slugify) changes the job.
Paste or type the input Safe Filename expects. Path hint: developer · filename safe. Replace illegal filename characters; length, case, spaces.
Apply the Safe Filename action only. CSS Identifier Escape is a different transform (CSS-escape identifiers with escape count.). Replaces < > : " / \ | ? * and controls. Optional replacement character, max length, lowercase, and space replacement. Unlike Slugify this can keep case and spaces. Unlike CSS Identifier Escape this is a filename, not a CSS ident. Empty names and . or .. fail.
Copy the output of Safe Filename if you need it elsewhere. Size/complexity still follows: Windows-illegal characters. Optional length cap 1–255. Empty, . and .. fail.
If the text job is actually Turn text into a URL slug with separator and length options., leave Safe Filename and open Slugify.

When not to use Safe Filename

Skip Safe Filename when a neighbor tool matches better — start with Slugify or CSS Identifier Escape — or when the description already warns the job will fail. In the tool’s own words: Replaces < > : " / \ | ? * and controls. Optional replacement character, max length, lowercase, and space replacement. Unlike Slugify this can keep case and spaces. Unlike CSS Identifier Escape this is a filename, not a CSS ident. Empty names and . or .. fail.

Questions about Safe Filename

What does Safe Filename do that other Developer pages on this site do not?: Replaces < > : " / \ | ? * and controls. Optional replacement character, max length, lowercase, and space replacement. Unlike Slugify this can keep case and spaces. Unlike CSS Identifier Escape this is a filename, not a CSS ident. Empty names and . or .. fail. Short version: Replace illegal filename characters; length, case, spaces.
Does Safe Filename upload my file or text to Tool-You servers?: No. Safe Filename runs in this browser tab. Files stay on the device. Limit note: Windows-illegal characters. Optional length cap 1–255. Empty, . and .. fail.
Should I use Slugify instead of Safe Filename?: Use Safe Filename when you need Replace illegal filename characters; length, case, spaces. Use Slugify when you need Turn text into a URL slug with separator and length options. They share a category (Developer) but not the same job.
What are the limits of Safe Filename?: Windows-illegal characters. Optional length cap 1–255. Empty, . and .. fail. Also: Replaces < > : " / \ | ? * and controls. Optional replacement character, max length, lowercase, and space replacement. Unlike Slugify this can keep case and spaces. Unlike CSS Identifier Escape this is a filename, not a CSS ident. Empty names and . or .. fail.