URL Slug & Clean Filename Sanitiser
Transform titles, article headlines, and dirty strings into clean, SEO-optimised URL slugs and safe filenames with diacritic stripping.
1. Raw String or Batch Lines
2. Sanitized Result & Safety Audit
Filesystem & Network Safety Diagnostics
- Pure ASCII compliant (No high-byte unicode or control chars)
- Windows & POSIX filesystem safe (No <>:"/\|?* or NUL chars)
- No Windows reserved device keywords (con, aux, nul, prn, com1-9)
- Within standard filesystem limits (68 / 255 chars)
Alternative Developer Formats
2026-developers-guide-building-high-speed-apis
2026_developers_guide_building_high_speed_apis
developersGuideBuildingHighSpeedApis
DEVELOPERS_GUIDE_BUILDING_HIGH_SPEED_APIS
About this tool
How to use it
- Enter your raw text, article headline, draft title, or file path list into the input box.
- Select your target environment: URL Slug, OS-Safe Filename (Windows/Linux/macOS), Cloud Storage Key (S3/GCS), Git Branch Name, or Database Column.
- Customize your separator (hyphen, underscore, dot, or none) and casing style (lowercase, UPPERCASE, or preserve).
- Toggle transliteration to convert international accents into Latin equivalents (e.g. ü → ue, é → e, ñ → n).
- Inspect the automated Filesystem and Network Safety Diagnostics to verify ASCII compliance and the absence of illegal OS characters or Windows reserved device names.
- Click 'Copy Sanitized Result' or 'Copy as URL Path' to paste directly into your code, CMS, or terminal.
Why it matters
Unsanitized strings cause broken web links, server 500 errors, security traversal vulnerabilities, and filesystem write failures across Windows and Linux environments. Automatically removing illegal characters (< > : " / \ | ? *), transliterating diacritics, and avoiding reserved device names ensures cross-platform software compatibility.
When to use it
Use when creating blog permalinks in WordPress/Ghost/Next.js, naming user-uploaded files, defining AWS S3 bucket object keys, naming Git branches, or generating clean database schema identifiers.
Good to know
Windows operating systems strictly prohibit filenames matching legacy DOS device names: CON, PRN, AUX, NUL, COM1 through COM9, and LPT1 through LPT9, even when given a file extension (e.g. con.txt). Our sanitizer validates against these reserved words.
Common questions
What characters are illegal in Windows filenames?
Windows prohibits nine characters: < (less than), > (greater than), : (colon), " (double quote), / (forward slash), \ (backslash), | (vertical bar or pipe), ? (question mark), and * (asterisk), as well as ASCII control characters (0-31).
What makes a URL slug SEO-friendly?
An SEO-friendly URL slug is lowercase, separates words with single hyphens (not underscores), contains relevant target keywords, strips filler stop words (e.g., 'and', 'the', 'of'), and excludes special symbols or URL-encoded percent signs.
What are Windows reserved device names?
Dating back to MS-DOS, Windows reserves names like CON (console), PRN (printer), AUX (auxiliary), NUL (null device), COM1-9 (serial ports), and LPT1-9 (parallel ports). Naming a file or directory with these keywords causes OS-level errors.
How does transliteration handle international characters?
The sanitizer uses Unicode Normalization Form KD (NFKD) to decouple diacritic accents from base Latin characters, converting accented characters (such as é, à, ç) into plain ASCII equivalents (e, a, c) and German umlauts (ä, ö, ü) into ae, oe, ue.
Does this tool transmit my filenames or code to external servers?
No. All text parsing, string transformations, and safety audits run 100% locally in your web browser memory with zero network requests.