# Slug Validator Validate URL slug strings (lowercase letters, numbers, hyphens only, no special characters) > Canonical page: https://elysiatools.com/en/tools/slug-validator - **Category:** Validation - **Keywords:** slug, url, validator, permalink, seo, friendly, url-safe, identifier ## Overview The Slug Validator checks if a string is suitable for use as a URL slug, ensuring it contains only lowercase letters, numbers, and hyphens for clean, SEO-friendly links. It helps maintain consistent and safe URL structures across websites. ## Inputs - **Slug** (text): Enter URL slug (e.g., my-blog-post, hello-world)... - **Allow Underscores** (checkbox) - **Max Length** (text) - **Allow Trailing Hyphen** (checkbox) ## When to use - When creating or editing URLs for web pages, blog posts, or products to ensure they are SEO-optimized. - To validate user-generated slugs in content management systems or forums before publishing. - When standardizing URL formats to prevent broken links and improve site navigation. ## How it works - Enter the slug string into the input field, such as 'my-blog-post' or 'product-123'. - Optionally configure settings like allowing underscores or setting a maximum length. - Click the validate button to instantly check if the slug meets the criteria. - Receive a clear result indicating whether the slug is valid or needs correction. ## Use cases - Validating blog post permalinks to ensure they are SEO-friendly and user-readable. - Checking product page URLs in e-commerce sites for consistency and safety. - Standardizing slugs in documentation or wiki platforms to avoid special characters. ## Frequently asked questions ### What characters are allowed in a URL slug? By default, only lowercase letters, numbers, and hyphens are allowed. You can optionally enable underscores. ### Why is slug validation important for SEO? Clean slugs improve readability for users and search engines, aiding in better indexing and higher rankings. ### Can I set a maximum length for slugs? Yes, you can specify a max length, with a default of 100 characters to keep URLs concise. ### What happens if a slug has trailing hyphens? Trailing hyphens are not allowed by default, but you can enable this option if your use case requires it. ### Is this tool free to use? Yes, the Slug Validator is a free online tool for validating URL slugs without any cost. ## Related tools - [Special Character Validator](https://elysiatools.com/en/tools/special-character-validator): Check if a string contains special characters like !@#$%^&*()_+ and identify which ones are present - [Credit Card Validator](https://elysiatools.com/en/tools/credit-card-validator): Validate credit card numbers and identify card type (Visa, MasterCard, UnionPay, etc.) - [EIN Validator](https://elysiatools.com/en/tools/ein-validator): Validate US Employer Identification Numbers - [ICCID Validator](https://elysiatools.com/en/tools/iccid-validator): Validate ICCID numbers for SIM cards with Luhn checksum and issuer analysis - [ISBN Validator](https://elysiatools.com/en/tools/isbn-validator): Validate ISBN-10 and ISBN-13 book number formats with checksum verification - [ISIN Validator](https://elysiatools.com/en/tools/isin-validator): Validate International Securities Identification Numbers (ISO 6166 ISIN) with Luhn check-digit verification, country/issuer prefix and NSIN breakdown. - [Luhn Checksum Calculator](https://elysiatools.com/en/tools/luhn-checksum): Validate or generate numbers using the Luhn algorithm (mod-10). 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