Replay is often compared with Sentry, but it’s not a case of one vs the other. They are complementary, and using them together will help you find, debug, and fix bugs/issues faster.
TLDR; Replay records your application’s runtime so you can debug it after the fact. Sentry monitors errors in production and gives you weekly reports providing a high-level overview of all the errors happening. Sentry does not have a debugger so in essence, if you see an error in Sentry and want to debug it, Replay is a great tool to reach for so you can capture the issue, reproduce and debug it on your machine.
Replay has a browser that records the runtime and then a debugger (DevTools view) which allow you to inspect elements and time-travel throughout the code’s execution to debug issues and land changes at every stage of development.
In this post, we’ll break down how they’re different and when you’d use Replay vs. Sentry
Replay is for recording everything happening in a particular session of the application. With Replay, we are recording everything, including the user events, network requests, the state of the application at every point in time, and what code was executing during the recording. This makes it particularly useful for reproducing issues and debugging.
Replay is a time-travel debugger that comes along with developer tools you’re familiar with from browsers and IDEs. While other debuggers require you to run your application again and again to debug, Replay provides all these tools in the context of the recording, so print statements can be added retroactively and you can inspect your application at any point in time from the session.
The output with Replay here is the shareable recording (called a replay) of the session that can be included on a support ticket, pull request, or anywhere else that context would be helpful. This replay serves as a single source of truth for collaborative debugging. You can add comments to the replay and store them in a team library for documentation of how bugs were reproduced and resolved.
Chrome Recorder, as the name implies, is specific to the Chrome browser and records manual user flows. Replay has versions for Firefox and Chromium, and can be used to record automated tests in CI. There is also [@replayio/node for recording Node runtimes](https://www.npmjs.com/package/@replayio/node), no browser required.