A URL shortener is a web service that transforms long, complex web addresses into significantly shorter, manageable links. When a user clicks the shortened link, they are automatically redirected to the original long URL.

How It Works

1. Input: You submit a long URL (e.g., https://example.com/very/long/path/with?parameters=123) to the shortener.
2. Mapping: The service generates a unique, short "alias" or identification code and stores it in a database alongside the original URL.
3. Redirection: When someone visits the short link, the service looks up the original address and sends an HTTP redirect command (typically a 301 permanent or 302 temporary redirect) to the visitor's browser. 

Key Benefits

• Space Efficiency: Essential for platforms with character limits, such as X (formerly Twitter) or SMS.
• Tracking and Analytics: Most modern services track click data, including the number of clicks, geographic location, device type, and referral source.
• Branding: Many services allow "branded links" or "vanity URLs" (e.g., yourbrand.co/sale), which can increase trust and click-through rates by up to 39%.
• Aesthetics: Shortened links look cleaner in marketing materials, emails, and social media bios.
• Link Management: You can often update the destination of a short link without changing the link itself, preventing breakage in printed materials or existing posts. 

Security Considerations

Shortened URLs can be used to hide the true destination of a link, which attackers may exploit for phishing or malware distribution. To stay safe, only click links from trusted sources or use "preview" features (like adding a + to the end of some shortened links) to see where they lead before clicking.