Replay.io

Overview

Replay.io is a time-travel debugging tool that records browser-based program executions and allows developers to replay them with full DevTools access. Unlike traditional debugging, Replay captures every event, network call, console log, and DOM mutation so developers can step backwards and forwards through execution. AI-assisted analysis helps pinpoint the root cause of bugs from the recording.

Use Cases

• •Recording flaky tests to capture intermittent failures for analysis
• •Debugging hard-to-reproduce production bugs with full execution replay
• •Sharing precise bug reproductions with remote developers
• •Stepping backward through code execution to find the root cause of errors
• •Analyzing React and JavaScript runtime behavior through recorded sessions
• •Integrating with Playwright and Cypress for test failure analysis

Features

• •Time-travel debugging with full execution recording
• •Forward and backward stepping through code
• •Full DevTools access on recorded sessions
• •Console log, network, and DOM mutation capture
• •AI-assisted root cause analysis
• •Playwright and Cypress test recording integration
• •Collaborative replay sharing and annotation

Integrations

Getting Started

1. 1Sign up at replay.io and install the Replay browser
2. 2Record a session by reproducing the bug in the Replay browser
3. 3Open the recording in the Replay DevTools
4. 4Use time-travel controls to step forward and backward through execution
5. 5Share the replay link with teammates for collaborative debugging

Practical Notes

• •Requires the Replay browser for recording; replays can be viewed without it
• •Free tier available for open-source projects; paid plans for private repos
• •Integrates with Playwright and Cypress to automatically record failing test runs
• •Most effective for complex, hard-to-reproduce bugs in web applications

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