Sizzy
Sizzy is a dedicated web development browser built to streamline responsive design testing and debugging workflows. It allows developers to view and test websites across multiple device dimensions simultaneously with synchronized scrolling, clicking, and form inputs. The tool includes specialized features for visual debugging, testing different user sessions and permission roles concurrently, capturing professional mockups, and managing responsive layouts without repetitive manual window resizing.
Checked on Oct 18, 2026.
Alternative resources
Responsively App
A developer tool that displays web pages across multiple devices simultaneously for responsive testing and layout verification.
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