Session replay shows you a visual reproduction of a visitor's journey on a website or app. It captures user actions like clicks, scrolls, and mouse movements, allowing you to see exactly how customers interact with your digital product. You can use it to find conversion obstacles, fix bugs, and understand why users behave the way they do.
What is session replay?
Session replay is a tool that recreates user sessions to provide a video-like view of the customer experience. While it looks like a video, it is actually a reconstruction based on data logs. These logs record every change to the Document Object Model (DOM), which is the code interface that translates web elements into objects that software can manipulate.
Unlike a screen recording or a movie file, a session replay tool strings together individual events, like keyboard entries or swipes, and overlays them on a snapshot of the website’s visual assets. This method allows you to analyze user flows without the heavy file size of traditional video.
Why session replay matters
Looking at raw numbers like bounce rates or page views often shows you that a problem exists, but it rarely shows you why. Session replay provides qualitative context to support your quantitative data.
- Solve conversion mysteries: You can see where users get distracted or which elements grab their attention before they leave a page.
- Faster debugging: Developers can view the exact steps a user took before an error occurred, leading to a faster mean-time-to-repair (MTTR).
- Improve customer support: Support agents can watch a customer's specific journey to understand a reported issue without asking for screenshots.
- Higher revenue: Finance company SoFi used session replay to find a form issue, which [saved an estimated $9 million in revenue] (Glassbox).
- Validate experiments: During A/B testing, you can watch how users interact with different variants to understand why one version outperformed another.
How session replay works
The technology behind session replay relies on two main components: assets and events.
- Asset Logging: The system takes a snapshot of the website's design elements, including HTML, CSS, and images.
- Event Capture: The tool logs every interaction as an "event," such as a mouse click, a tap, or a window resize.
- DOM Mutation Tracking: The tool records every change made to the Document Object Model. This includes when a user enters text or when a new menu appears.
- Reconstruction: The replay engine combines the design snapshots with the interaction logs to play back the session in a format you can watch.
Capture methods
There are different ways to record these sessions, each with specific advantages and weaknesses.
| Type | How it Works | Pros | Cons |
|---|---|---|---|
| Tag-based (Client-side) | Uses a script on the page to record actions in the browser. | Highly accurate for mouse movements and scrolling. | Can be blocked by adblockers. [Adblockers were active on 615 million devices] (Blockthrough) as of 2017. |
| Tag-free (Server-side) | Captures traffic directly from the server. | Cannot be blocked by browsers; good for compliance. | Cannot see client-side actions like mouse wiggles or scrolls. |
| Hybrid | Combines server-side recording with client-side tracking data. | Records 100% of sessions while maintaining visual detail. | Often requires more complex implementation. |
Best practices
Mask sensitive information. Use default privacy settings to automatically hide names, credit card details, or passwords from the replays. This helps ensure compliance with regulations like GDPR.
Use filters to find struggle. Don’t watch every session. Filter for "rage clicks" (when a user clicks the same spot rapidly) or "dead clicks" to find where users are frustrated. Some advanced tools offer [automated struggle detection] (Sessioncam) to surface these sessions.
Integrate with other tools. Combine replays with Error Tracking or Application Performance Monitoring (APM). Seeing the backend code performance alongside the user's view gives a complete picture of an error.
Save past designs. Many tools only show the most current version of your site. If you change your layout, you may need to manually save past versions to ensure your old replays still look correct.
Common mistakes
Mistake: Sifting through thousands of replays manually to find insights. Fix: Use AI-generated context or [session summaries] (Fullstory) to get a quick overview of what happened in a session before watching it.
Mistake: Ignoring user privacy and security requirements. Fix: Ensure your tool uses Role-Based Access Control (RBAC) so only authorized employees can view user sessions.
Mistake: Assuming session replay impacts site performance. Fix: Choose tools optimized to capture DOM mutations without slowing down the user's browser experience.
Examples
Example scenario (E-commerce): A marketer noticed that users from a specific social media campaign were dropping off on the checkout page. By watching session replays, they saw that a promotional pop-up was covering the "Pay Now" button on certain mobile devices.
Example scenario (Product Development): A product team released a new search filter feature. By watching replays, they realized users were clicking a non-clickable icon instead of the actual filter button. They adjusted the design to make the button more obvious.
Session Replay vs. Heatmaps
| Feature | Session Replay | Heatmaps |
|---|---|---|
| Data Type | Qualitative (Individual journeys) | Quantitative (Aggregated data) |
| Goal | To see "Why" a single user struggled | To see "Where" most users click/scroll |
| Best Used For | Debugging and UX research | Identifying page-wide design trends |
| Input | Sequential list of all actions | Color-coded density of actions |
Rule of thumb: Use heatmaps to find the pages that need help, and use session replay to figure out exactly how to fix them.
FAQ
Is session replay an actual video recording? No. It is a reconstruction of events. The software logs interactions (clicks, scrolls) and design changes in the browser, then plays them back like a movie. This makes the data much smaller than an actual video file and allows for better privacy masking.
Do I need to tell users I'm using session replay? Yes. You should disclose the use of session replay and similar analytics tools in your privacy policy. Most tools offer masking features to hide sensitive data like payment information to stay compliant with privacy laws.
What are rage clicks? Rage clicks occur when a user clicks an element multiple times in very quick succession. This is usually a sign that a button is broken, a link is dead, or the page is responding too slowly. It is a primary indicator of user frustration.
Can session replay track mobile apps? Yes. Mobile session replay captures taps, swipes, and pinches instead of mouse movements. It also captures device-specific data like screen orientation and model, which helps find bugs specific to certain hardware.
Does session replay capture other apps on a user's computer? No. Session replay only records what happens within the specific browser tab or app where the tracking script is active. It cannot see notifications, other open tabs, or any activities outside the window.
