URL Expander

URL shorteners create short aliases that redirect to longer URLs. When you visit a short URL, the service performs a 301/302 redirect to the target. Services track clicks, geography, referrers, and devices for analytics. Popular services: bit.ly, TinyURL, t.co (Twitter), goo.gl (deprecated). While convenient for sharing, shorteners create transparency issues and dependency on third-party services for link persistence.

Not automatically. While major shorteners (bit.ly, TinyURL) scan for malware, they can't detect all threats, and attackers constantly create new malicious sites. Shortened URLs are common in phishing because they hide destinations. Always expand before clicking, especially in emails, SMS, or social media from unknown sources. Look for warning signs: unexpected domains, Unicode tricks, typosquatting attempts.

Expanding reveals: final destination domain, path and parameters, redirect chains (multiple hops), HTTP status codes, whether HTTPS is used, potential tracking parameters (utm_source, etc.). Some expanders show page titles, reputation scores, or malware scan results. Analyze parameters for data being transmitted, check domain reputation, verify HTTPS certificates for sensitive transactions.

No. Expanders reveal destinations but can't detect all threats: zero-day exploits, time-delayed attacks (show legitimate content initially), geo-targeted attacks (show different content based on location), or sophisticated phishing using legitimate-looking domains. Combine expansion with URL reputation services, malware scanners, and security awareness. When in doubt, don't click—contact sender via alternative channel to verify.

Attackers use shorteners to: hide malicious domains from email/social media filters, bypass URL blacklists (shortener domain is legitimate), track victims (click analytics), enable rapid URL switching (change destination without changing short URL), and create urgency (short URLs look time-sensitive). Some shorteners allow custom aliases, enabling social engineering (bit.ly/company-invoice). Always verify before clicking shortened links in unexpected contexts.

Preview features fetch and display destination page content without full visit: page title, meta description, screenshot, SSL certificate info, reputation scores. This provides additional context for legitimacy assessment. However, preview requests still contact the server, potentially alerting attackers or triggering tracking. For highly suspicious links, use sandboxed environments or dedicated security services instead of direct preview.

Consider blocking unknown shorteners while allowing approved ones (bit.ly, t.co) in web filters. Blocking prevents shortened malicious links but may impact legitimate business communications and social media. Alternative approach: expand URLs at email gateway, show destinations to users, and scan expanded URLs for threats. Train users to recognize risks and verify unexpected shortened links through alternative channels before clicking.