Insights · 9 min read

The top technical considerations when assessing session replay solutions

Joel Webber
Posted June 08, 2023
The top technical considerations when assessing session replay solutions

In the world of session replay, there are plenty of tools out there that can show you approximations of what your users saw and did on your site or app. But too often, they’re just that: approximations. 

When done right, session replay can be far more than the sum of its parts. While a shortcut session replay provider might save you a few dollars up front, the long-term costs and risks of approximated session replay will quickly outpace the benefits. In a previous article, we talked about how the best version of session replay is operational: fitting into and empowering your teams’ existing workflows rather than acting as an add-on or afterthought. 

Most session replay tools record session data and event data separately, then piecemeal these datasets together. This tells an incomplete story because it limits the interaction data that’s captured. 

On the other hand, operational session replay uses autocapture to extract and analyze all events on the server, making session data the source for all ensuing digital experience insights. This means a client receives complete digital experience data that can be retroactively analyzed without introducing the security and performance risks inherent in other methods of capture. 

Ultimately operational session replay helps you grow revenue smarter, save time and money, and innovate with confidence on web and mobile—and you shouldn’t settle for anything less in your tech stack. 

Fullstory’s session replay has been built from the ground up to provide complete, high-performance session replay that’s low-lift for your team. Here, I’m going to walk you through the technical foundation that sets operational session replay apart from lesser versions. 

Operational session replay helps you grow revenue smarter, save time and money, and innovate with confidence on web and mobile—and you shouldn’t settle for anything less in your tech stack.

fs-inpagecontent-the norm

Accuracy, fidelity, and completeness

Fullstory’s Digital Experience Intelligence (DXI) platform is built on top of a patented data engine that captures and interprets complete, reliable session data to power your insights. Here’s how Fullstory ensures you have accurate, complete, high-fidelity digital experience data at all times.  


Fullstory’s proprietary approach to session replay is to autocapture sessions completely and accurately, then extract insights and analytics from that session data. Other session replay tools use a more old-school approach that requires users to instrument or tag the events they want to analyze–instead of enabling tagging as an option–and then add on session replay as a sidecar. Because the analytics data doesn’t come directly from the sessions in this method, the product analytics and session replay insights won’t be a perfect match, which can leave detrimental blind spots in your analyses.

Because the analytics data doesn’t come directly from the sessions in this method, the product analytics and session replay insights won’t be a perfect match, which can leave detrimental blind spots in your analyses.

Broad feature support for mobile

Teams need a DXI platform that understands the complexities of ever-evolving app frameworks. Fullstory for Mobile Apps was built to be compatible with as many apps as possible, supporting platforms and frameworks that are:

  • Used most often for building mobile apps (including Swift, SwiftUI, and Java)

  • The most sensible and relevant for developing mobile apps

  • At the cutting edge of app development trends

We stay on the pulse of app framework development. When a new framework comes on the market, we go through an auditing process to determine if Fullstory should support it. 

One of the most important requirements we look for is whether the framework meets our privacy and performance standards. If it passes the audit, we then scope the work we need to complete to support it. That means you get to stay at the forefront of app development without sacrificing the DXI you need to make your app stay great.

Your engineers are constantly improving your app—make sure you have a DXI platform that can keep up. 

Tabbed browsing

The average person has nine browser tabs open at any given time, including multiple pages from the same website to make it easier to browse. Fullstory is the only digital experience solution that can provide a complete view of how your customers navigate between multiple browser tabs on your website. With tabbed browsing in session replay, you can understand how users move around your site more clearly than ever. 

Though tabbed browsing has become an increasingly popular way to navigate the internet, it’s historically been very difficult for companies to understand what prompts users to open new tabs, what they’re doing in each tab, and how they move between them. Now, with Fullstory session replay, this DX data is readily available. 

Debugging tools

The depth of Fullstory’s session data provides invaluable context for reproducing and fixing bugs. With access to network and console data, engineers using Fullstory can debug with lightning efficiency. 

  • Console: The Fullstory Console view allows you to capture messages reported in a customer's browser's console. When Fullstory captures those Console messages, such as console.log(), console.error(),, and console.warn(), you can see errors that occur "in the wild," so you can zoom in on exactly what caused errors to occur, giving you more time to go back to doing other things.

  • Network Capture: Network Capture provides the ability to identify and analyze Network errors via DevTools in Session Playback for mobile sessions. This gives you the ability to create segments and funnels based on common network errors for Mobile Apps to understand their impact and prioritize fixes accordingly.

“A huge factor for our engineering teams in terms of making their productivity quicker is that Fullstory captures all of the data. They can get data points from sessions that [our previous vendor solution] didn’t capture, which makes reproducibility much quicker.” Senior director, retail

Download the complete TEI study to learn how Fullstory helped an enterprise organization save $511,000 in increased productivity.

Complete, reliable data

When it comes to capturing digital experience data on your site or app, relying on sampling is necessary in many instances. However, your digital experience solution should never force you to rely on random sampling as the basis of your analyses. After all, how can you find, quantify, and fix DX issues if you don’t have an accurate representation of your digital experience? 

The breadth of DX events Fullstory can produce and analyze is greater than other solutions because the events are extracted from session data. Because the event extraction is not running on the client’s side, Fullstory can handle most queries retroactively (rather than needing to tag first and then capture them), so you can answer questions as they crop up. 

Here are three examples of powerful Fullstory insights that would be impractical or impossible to extract on the client’s side: 

  • Dead Clicks, a key frustration heuristic, relies on the ability to correlate user actions with DOM changes across time. This would be difficult to do on the client’s side. 

  • Pinch-to-zoom, another frustration signal captured in Fullstory, requires a complex analysis of tap gestures. 

  • Detections, an important privacy feature, requires deep scanning of all session data. 

Retroactive queries require an indexing system that allows interactive search across the extraordinary number of events that autocapture generates. Fullstory is the only tool on the market that has the ability to index DX events at this scale. 

Autocapture is only as useful as its safety features, though. Fullstory’s Private by Default approach ensures that no page elements are captured unless specifically allow-listed. This can include images, prices, inputs, product names, URL parameters, network data, and much more. Fullstory is able to accurately capture a mixture of masked and unmasked content on the web without losing fidelity or breaking the layout. Many DX tools claim to be “private by default,” but can actually only deliver this capability on form fields (which aren’t as fragile as other page elements). To be able to fully trust your solution’s privacy capabilities, you need to be absolutely certain that it’s masking everything potentially sensitive right out of the box—even things you don’t see like network data information and URL parameters. 

Privacy and security

Fullstory’s session replay was built to deliver maximum digital experience insights while maintaining end-user privacy every step of the way. With industry-leading privacy controls, Fullstory ensures session replay remains flexible and private-by-default across all data types. Here are a few ways we accomplish this:

  • Authorized Fullstory users are able to mix and nest masked and unmasked privacy rules in the app structure

  • Through network and URL capture, without the need to explicitly mask unsafe values

  • Create and mix privacy rules are both in code and in configuration

  • Detections and Redactions are available to deal with any accidental leaks

What’s more, because Fullstory extracts events on the server, there’s no need to ever deploy poorly vetted, workaround scripts to a customer’s site that could open it up to risks. (We’ll cover this more in a later section.) 


Your quest to understand bugs and digital experience issues should never create more issues for the end-user. That’s why Fullstory is built to have the lightest possible touch on the client, ensuring it never has a noticeable impact on site or app performance. 

How? We use: 

  • Less thread blocking than other DX platforms

  • Optimized wire format that doesn’t rely on background compression to hide chatty protocol

  • No video or screenshots on mobile capture, which dramatically reduces CPU and network load (more on that here)

Internal work and maintenance 


Many session replay platforms require some level of customization to get them up and running on your site or mobile app. Relying on your vendor to write bespoke code isn’t ideal for multiple reasons: 

  • It adds substantial time to value for your organization 

  • It introduces the security risk of having a vendor write code to your website on your organization’s behalf

  • It doesn’t result in retroactive data

Implementing Fullstory is as simple as adding the data capture snippet into the <HEAD> element either via your Content Management System (CMS) or directly into your application’s code. Because there’s no tagging required to begin capturing sessions, your digital experience data is retroactive and searchable by design. 


Session replay tools that require heavy tagging or instrumentation require a significant amount of labor to continue to capture the data you care about. And when the data you care about changes, your tags will have to change too. Whether your internal team or your vendor is doing that work, your organization is paying for it. With operational session replay, the data you care about (and the data you didn’t even know you would care about) is at your fingertips with very little upkeep.

You’re probably already leveraging session replay to understand your digital experience. But are you settling for a bolted-on version of session replay that isn’t operational? At best, you’re likely missing out on insights and data. At worst, tools like this could actually do more harm to your digital experience than good. 

Learn more about how Fullstory’s patented DX data engine helps you pinpoint bugs and prioritize fixes here.

Joel WebberCofounder & Engineering

About the author

Joel Webber is a Co-Founder and Chief Architect at Fullstory. He is based in Marietta, Georgia.

Return to top

Related posts

Blog Post
6 key metrics in measuring customer experience (CX)

Learn to measure customer experience with six essential metrics. Understand customer perceptions, improve service quality, and increase loyalty.

Read the post
Blog Post
A guide to the most important CRO metrics

Find out what CRO metrics you need to track, and why.

Read the post
Blog Post
Best practices for enhancing digital experience with analytics | Qualtrics

Learn best practices for using digital analytics to design exceptional customer experiences in this guide.

Read the post