Responsive tester is an Astrina tool for CSS and front-end design. Previews at phone, tablet and desktop widths. It opens the page in a real browser on our render cluster, giving accurate results for JavaScript-heavy sites.
How to use Responsive tester
- Enter the URL of the page.
- Click "Run the check."
- The page opens in a real browser on our servers — this takes 10–20 seconds.
- Review the screenshot or metrics when the job completes.
What Responsive tester is used for
Professionals working in CSS and front-end design use this tool to save time and catch errors before they become problems. Common use cases:
- Auditing and quality checks in CSS and front-end design
- Validating or converting output before deploying
- Debugging issues quickly without switching between multiple tools
- Generating boilerplate output to speed up development
Key features
- Fast: server-side analysis in seconds
- Free for most use cases — no account required for the majority of checks
- Accurate: uses the same techniques as professional SEO and security scanners
- Privacy-friendly: we do not store the content we analyse beyond the session
About this tool
This is part of Astrina's suite of 21 CSS and front-end design tools. All tools are available at astrina.io/utilities.
Frequently asked questions
Is Responsive tester free?
The tool is free to use for basic runs. Daily limits apply for server-side tools without an account; a free account raises those limits.
Do I need an Astrina account?
For most checks, no account is needed. An account is required for higher usage limits or paid features.
Can I use Responsive tester through the API?
This tool runs through the web interface. API access is available for selected fetch and network tools.
How accurate is Responsive tester?
The tool uses the same techniques as professional SEO and security scanners. Results reflect what search engines and browsers actually see.
Try the Responsive tester now — no account required for most checks, and the result is ready in seconds.
