- Overview – who this is. The person and their properties, the screen they were on, which experiment variants they got, and who else on your team has already watched this replay.
- Inspector – events and errors captured during the session on a synced timeline. Your events, console logs, network requests, and comments, filterable down to one kind at a time.
- Network waterfall – what the page was waiting on. Every request laid out by time, so a slow screen in the replay has something to blame.
- Observations – what Replay Vision found in this session without you watching it.
- Linked issues – create or find related issues in your issue tracking tool.
Session Replay 101
Session Replay records what real users do in your product and plays it back like a DVR, with a synced dev tool panel showing console logs, network requests, and errors at the exact moment they happened.
Anatomy of a replay
When you head to Session Replay in PostHog, you'll be greeted with a player Fig. 1 with all your recordings. You'll spend a lot of time here, so let's go on a tour.
Select a session on the left and it plays back in the middle, with everything PostHog knows about it on the right. That context is what makes PostHog's Session Replay powerful.
Session context
The right-hand inspector lets you watch replays in context of your PostHog data. They add context so you can answer the who, what, when, where, and how of each replay. You can follow from replay to persons, events, logs, errors, and more.
You'll find them all on the right of the player Fig. 2.
What's actually recorded
Recordings come from your PostHog SDKs. Session Replay is supported by the JavaScript web, React Native, iOS, Android, and Flutter SDKs.
These replays are not videos on the web. The SDK takes a full snapshot of the page's DOM, then records only what changes – clicks, scrolls, mutations – and the player rebuilds the page from that stream. This helps keep cost low and minimize performance implications.
| SDK | What it records |
|---|---|
| JavaScript web | The DOM, rebuilt in the player |
| Android, iOS | A wireframe of the view hierarchy, rather than the real look and feel, unless you turn on screenshot mode |
| React Native, Flutter | Always screenshot mode |
Install and turn it on
None of it works until a PostHog SDK is in your app. The wizard installs and configures one for you, or you can install it yourself.
npx @posthog/wizardRecording is a project setting as well as an SDK one, so switch it on in project settings before you expect to see anything. We'll go over configuration decisions in the next page.