Automatic Browser User-Agent Checker

When you access this page, your current browser’s User-Agent is displayed instantly.
Easily check it on mobile too — perfect for testing and debugging.

👉 Quick Access Link: https://vvd.im/agent

Automatic Browser User-Agent Checker

Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)

Why ‘User-Agent’ verification is essential for successful web development and debugging

When developing a website, you often encounter cross-browsing issues where CSS or JavaScript behaves differently depending on the browser (Chrome, Safari, Firefox, etc.) or operating system (Windows, macOS, Mobile) environment.
The ‘Vivoldi’ User-Agent checker is an essential utility to quickly and accurately diagnose these fragmentation issues.

  • Instant Response to Browser Updates: Instantly check the subtly changed rendering engine info and User-Agent strings whenever major browsers update their versions, preventing logic errors in advance.
  • Mobile and Desktop Environment Testing: When debugging how a web page should render based on the connected device, you can grasp the exact access environment info at a glance without opening cumbersome developer tools.
  • Easy Data Copying and Application: Copy the identified long string to your clipboard with a single click and paste it directly into server log analyzers or code editor conditional statements to maximize workflow efficiency.

Have questions?
Check the FAQ.

A User-Agent is a string automatically sent by your browser when accessing a website, including browser type & version, rendering engine, and operating system details.

Common browser examples: Chrome, Edge, Safari, Firefox, Naver Whale, etc.

Example: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36

  • Usage: Site analytics, customized UI, debugging, service quality improvements.
  • Note: Strings may vary with browser & OS updates, so they have limitations for absolute identification.

User-Agent data identifies browser, operating system & device, helping websites deliver optimized experiences tailored to each environment.

  • Customized UI: Platform-specific features, linking to app stores (App Store & Google Play, etc.).
  • Analytics & Marketing: Visitor environment analysis, marketing strategy development.
  • Security & Operations: Detecting abnormal access, debugging browser-specific issues, strengthening policies.

While browser compatibility has improved significantly, User-Agent data remains vital for optimization and site management.

For everyday browsing there’s no issue, but in cases like web development & app integration & site error diagnosis & browser compatibility testing, you may need to verify the actual User-Agent value.

  • When a site feature doesn’t work properly.
  • When customer support requests your “User-Agent value.”
  • When developing or testing apps or browser extensions.

With this tool, you can instantly view, copy, and share the real User-Agent, making it essential for troubleshooting, service improvement, technical support, and development collaboration.