Sizzy

Sizzy makes a browser for web developers and designers to test responsive websites across multiple screen sizes in one window. Its synchronized device previews share scrolling, clicks and form inputs, letting users check layouts and interactions without repeating each action. Universal DevTools provides a shared debugging panel, while Session Manager supports different accounts on different devices for testing permissions and user roles. Project workspaces save configurations, and Photo Studio creates device mockups for presentations and documentation.

Created by Kitze, Sizzy began as an open-source web app addressing the repetitive work of previewing client websites. It evolved into a paid Electron browser, with Praneet Rohida helping launch the commercial product in 2019 as a founding engineer and lead developer. Its Chromium foundation supports Chrome extensions, while device simulation accounts for pixel ratios, user agents and browser interface height. The product expanded in 2026 with built-in AI coding agents and an integrated terminal.

In 2026, the company reported 10,000+ developers and 738 releases since 2018. Its commercial model includes monthly and annual subscriptions alongside lifetime access. Listed 2026 prices were $15 monthly, $144 annually or $499 for lifetime access, with a 14-day trial requiring no credit card.