Responsive device preview with real browser simulation for frontend developers.
Users
4
0 in 30 days
Rating
5.0 / 5
unchanged in 30 days
Ratings
1
0 in 30 days
Store rank
#266K
#222K among extensions
Version
1.0.1
updated 10 May 2026
Users
monthly, 5 months
Latest, 16 Oct 2026:4 usersMove the mouse over the chart for any month
Ratings count
monthly, 5 months
Latest, 16 Oct 2026:1 ratingsMove the mouse over the chart for any month
The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.
About Forma
Forma: Test Responsiveness Like a Pro
Building responsive websites? Forma is your ultimate companion for testing how your pages look across all devices. With a single click, simulate everything from a tiny smartphone to a massive TV screen—no need for physical devices or complex setups.
Why Forma?
Multi-Device Preview: Test your webpage on custom or preset device dimensions (e.g., iPhone, iPad, desktop, 4K TV).
Real-Time Updates: Adjust the viewport size and see changes instantly as you code.
Custom Dimensions: Define your own device profiles or use built-in presets for popular devices.
Side-by-Side Comparison: View multiple device previews simultaneously to spot inconsistencies.
Lightweight & Fast: No lag, no bloat—just seamless responsiveness testing.
How It Works
Install Forma from the Chrome Web Store.
Open the extension and select a device preset or enter custom dimensions.
Resize the preview window or use the toolbar to switch between devices.
Test interactively—scroll, click, and hover to ensure everything works perfectly.
Save your favorite setups for quick access in future sessions.
Perfect For
Developers who want to ensure pixel-perfect responsiveness.
Designers validating layouts across breakpoints.
QA Testers checking cross-device compatibility.
Freelancers/Agencies delivering flawless client projects.
Stop guessing how your site looks on other devices. Install Forma and test with confidence!