Replay is a time-travel debugger for web applications that allows developers to record, replay, and debug their code with unprecedented precision. Founded by Jason Laster and Brian Hackett, Replay enables developers to capture entire browser sessions, including user interactions, network requests, and application states, and replay them down to individual lines of code. The platform works by intercepting low-level system calls made by the browser and recording them, creating a simulation that can be played back as if running on a normal computer.
Replay's core functionality revolves around its ability to record browser sessions using forked versions of Firefox and Chrome. Once recorded, developers can share these sessions via URL, allowing team members to collaboratively debug issues without needing to reproduce them. The platform integrates familiar browser developer tools, enabling users to add print statements retroactively, inspect application states at any point in time, and even run the code backwards to trace the origins of bugs. This approach significantly reduces the time spent on reproducing and diagnosing issues, with some users reporting a reduction from 1-2 hours per day to just minutes.
Key customers and partnerships
Replay has been adopted by various companies and projects in the software development industry. Firefox integrated Replay's technology to address issues that were difficult to reproduce consistently. The platform has also been used by companies like Glide, where the CTO was able to record a bug and share it with the engineering team for quick resolution. Replay is working with projects such as XState, Excalidraw, and React DevTools to update their issue templates to accept replays, facilitating easier bug reporting and resolution. The company plans to expand its capabilities to address visual and networking bugs.
By using this site, you agree to allow SPEEDA Edge and our partners to use cookies for analytics and personalization. Visit our privacy policy for more information about our data collection practices.