The definitive guide to session replay

Session replay reproduces your user's online experience like it's video. But how should you use it?

Discover why product managers, ecommerce directors, and everyone in-between is turning on the power of searchable session replay

All web analytics tools exist to solve a fundamental problem: provide actionable, reliable, and timely insights about the user. Understand the real-life person engaging online, on the other end of the screen:

» What's the customer trying to do? » What is their experience really like? » What works? What breaks? » When, where, and why do users get frustrated?

Traditional analytics tools answer these questions by turning users into numbers: clicks, bounce rates, page visits, conversions, and other abstractions. While this data feels insightful, analytics are always an abstract representation of what' actually happening.

Traditional web analytics miss the forest for the trees.

That's where session replay comes in.

Session replay tools definitively answer the question, "What's happening on my site (or app)?" Replay goes beyond traditional web analytics tools by taking a complete picture of the user on a website or app. They provide all the individual data points you get with a typical analytics tool and how those data points combine to create an experience.

The result? Everyone from product managers to tech teams to support agentsmarketing to sales, and everyone in between are turning to session replay to understand the user on the other side of the screen, learn from their struggles and successes, and build better products. SaaSecommercefintech? No matter the industry, if your business is online, replay is for you.

With session replay you can finally get the answers you need to understand your customers and improve their online experience.

1. What is session replay?

Session replay is the reproduction of a user’s interactions on a website or web application exactly or as close as possible to how the user actually experienced it. Session replay tools capture things like mouse movements, clicks, typing, scrolling, swiping, tapping, etc.

Watching a session replay is like watching a video reproduction of what a user did on a web site or app.

Below, press play to replay the recorded session of a fictional user interacting with this guide on our old website:

Session replay may also be known as session playback, session recording, user replay, user experience (UX) replay, or even mouse recording, among other names, and has existed for longer than you think—over 10 years.

What session replay isn’t

Most session replay tools don’t rely on actual video. Rather, they reconstruct events as they occurred.

Imagine someone took detailed notes about your day—down to where you were, when, what it looked like, what you did, how you acted, etc. Then, they took those notes, rebuilt the scenes and hired actors to play the parts, using the notes like a script to recreate the day just like it actually occurred. If you watched this recreation, while it would look like a video, it’d be more like a play.

That difference, while subtle, is important because unlike video, session replay is immensely rich in meaningful data—data more powerful session replay tools can mine for insights, use to segment users by behavior or interaction, and even use for machine learning.

But we’re getting ahead of ourselves.

2. How session replay works

We hear these kinds of things a lot:


What is this magic?

That's incredible!

When you first watch a session replay, it can be a surreal experience—how did you create a video of a user's online experience?

Realizing that it's not video, but a high-fidelity reproduction of a person's experience adds to the mystery—how is this possible?

It's complicated, so let's dive into the technical specifics of session replay.

DOM straight!

You can’t talk about session replay without invoking the DOM or Document Object Model, which is how users experience and interact with the web.

Replay captures everything that occurs in the DOM. We'll avoid going into a detailed explanation of the DOM (For that, Google DOM); however, having a working analogy of what the DOM is will help you understand how session replay works.

Imagine your website or app is a building. The DOM is the physical structure of the building—the foundation, the plywood frame, the doors and windows, and so on. HTML, CSS, and JavaScript control how the house is constructed, how it looks and how it behaves.

By recording the DOM and all mutations to the DOM that occur throughout a user's visit to this "building," a session replay tool can accurately record and recreate not only the building itself but all the times a user walked through a doorway, moved a piece of furniture, hung a painting on the wall, or even did some remodeling. By additionally saving copies of all the assets that make up the building’s appearance, session replay tools can recreate the unique way the building looked at a specific point in time as well as across the duration of the time spent in the building—even if the building changes in the future.

Our physical building analogy is analogous to what session replay tools accomplish virtually. Session recordings provide the necessary bits and pieces you need to replay how users experienced your web site or app for the explicit purpose of understanding that experience—to learn from it and improve that experience for future users. (More on this in What is Session Replay Useful For? below)

Rounding out our building metaphor, in session replay, the building materials as well as the activities that occur within the building can be classified into two categories: events and assets.

Events: Session replay building blocks

Every action that takes place on the web requires the transfer of information. While the experience is seamless to the user, when the mouse moves, the screen swiped, or anything done, at all, information is created. All of those information transfers are tiny events.

Session replay is a reconstruction of all of those events from an extremely detailed log.

Assets: Session replay building blocks

In addition to the events logged, the “scene” within which the events took place must also be captured. That’s why session replay tools also record the associated web assets—that is, all the bits and pieces (E.g. images, HTML, CSS, etc.) that are used to build what you see on a web site or app. Saving the assets is important because session replay tools that do not cache assets are unable to reproduce older sessions if and when the web page or app changes.

What can be recorded?

Websites are often complex. Many web pages and apps invoke JavaScript or AJAX, are responsive in design, and dynamic by default. What about mobile? What about variations in screen resolution, browser window size, etc.? Web apps have different states with windows that pop-up, menus that explode out (and disappear), and any number of other complications. For session replay tools to be useful, they need to be capable of dealing with all of this complexity.

Below is a partial list of all the things that can be recorded in session replay—note that not all session replay vendors record all of these things (See finding the right session replay vendor, below for more discussion on this).

  • HTML and CSS (And all the most basic web page and app elements)

  • CSS animations

  • Vector graphics in SVG (including animations)

  • Hover cursors and effects

  • Embedded <iframe>s

  • Script-modified input values

  • Window resizing

  • AJAX URL navigation

  • HTML5 <audio> and <video> playback

  • Multi-touch events (on mobile devices)

  • Web Components, and by extension, Shadow DOM

One of the compelling aspects of session replay is that it captures all the nuance experienced by users—nuances of your web site or web app and nuances in user devices, browsers, window sizes, etc. It works across devices including mobile—though there are no session replay tools that record native-Mobile app sessions as of late 2017.

What can't (yet) be recorded?

Alas, there are some things that session replay can’t do. Here’s another partial list—though one that is changing as the technology evolves:

  • Canvas

  • WebGL

  • Plugins such as Flash, Java, Silverlight, etc.

  • Local resources (E.g. "blob" URLs, Cordova apps, and Chrome extensions)

3. What about session replay and privacy?

Knowing session replay exists may trigger an uncomfortable reaction: is the level of visibility allowed by session replay tools too much?

FullStory and privacy

Privacy is of the utmost importance to FullStory. FullStory requires users to exclude sensitive information from being recorded along with a detailed Acceptable Use Policy that users must agree to in order to use FullStory session replay.

The privacy of your customer data is a shared responsibility. FullStory diligently ensures that your customer data is securely stored and accessible only to you.

Session replay tools, like other web analytics tools, require disclosure to users via language in your privacy policy, notification, pop-up, etc. If you use other analytics or customer-experience services (E.g. Google Analytics, MixPanel, Segment, Tealeaf, Omniture, Intercom, Optimizely, and hundreds more), you very likely already placed such a disclosure on your site. That’s because the techniques used by these popular platforms to collect your customer’s data are fundamentally no different.

Additionally, a session replay tool should provide for the exclusion of sensitive data from being recorded (e.g. passwords). An additional complexity around privacy and session recording is that each session replay tool approaches privacy and implementation of their recording scripts differently.

The choice to deploy a session replay tool on your web site or app requires careful assessment of the session replay provider and their security protocols. It also demands thoughtful consideration around user trust. These considerations must be carefully weighed against the benefits of using a session replay tool to improve the online experience of your users.

4. What is session replay useful for?

Now that you understand that session replay is a video-like reproduction of the customer experience online, you might be wondering, "Okay, what can you do with that?" The answer is: a lot.

Session replay is the firehose of information about the online experience. As you get comfortable with navigating the massive amount of information captured by a session replay tool, you will discover new ways to mine your sessions for insights—things that you never could have done with a traditional web analytics platform.

If you're new to session replay tools, the following use-cases will help familiarize you with what's possible with replay.

15 problems solved by session replay

Below are 15 common problems solved by session replay tools. For the first four—reproduce and solve bugs faster, conversion rate optimization (CRO), support customers faster through context, and understand the user experience (UX)—you'll find detailed explanations of the problem as well as supporting stories to how session replay was used to solve the problem.

1 | Reproduce and solve bugs faster

A near unlimited number of things can go wrong with products that live online. The variation in devices, OS, browsers, screen sizes and resolutions, all introduce variables that make QA and software testing tedious, error prone, and inevitably limited in scope.

When things break and bugs are reported, chances are the problem won't be reproducible—or can't be reproduced without dedicating hours of the dev team's precious time.

Common problems engineers and product developers encounter include:

» I need to reproduce bugs in order to understand them, but bug reports don’t tell me enough information to deduce what’s going on.

» I can’t figure out when my app/site is having errors.

» I need to know who's been affected by a bug.

» I need a way to prioritize bugs by impact.

Session replay is a game-changer for solving bugs. By tying user session links to bug reporting tools (e.g. FullStory integrates with JIRA or BugSnag to make this process seamless) and customer support tickets (See 3. Support Customers Through Context below), you never need to ask for a screenshot or ask for additional details about "what went wrong."

With session replay tools that capture all sessions, QA and software testing doesn't stop at launch. Indeed, session replay can be used alongside product launches, allowing product developers to observe as users engage with a new feature or interface and make sure it's working correctly. In the likely event something is broken, replaying sessions will show just what caused the problem, ensuring it gets fixed quickly.

Depending on the capabilities of the tool—replay may also include things like stack traces, Network views, .HAR, UserAgent info, and more (See FullStory's Dev Tools).

Select session replay tools also empower you to search for sessions containing “Error Clicks” (Find how to examine session replay tools below). Pairing session recordings with console logs makes for a powerful way to eliminate JavaScript errors on your site.

Below are examples of how session replay was used to reproduce and solve bugs faster, saving developers' time and companies' money:

  • Moosejaw — retail/ecommerce — time saved solving bugs with replay has enabled them to go beyond reactive bug-fixing to proactive bug-finding.

  • Breather — innovative workspace provider — session replay helped solve difficult to see UX problem.

  • GenM — education — on saving 500+ hours of QA time by catching and reproducing bugs with session replay.

  • thredUP — ecommerce, retail — thredUP combined session replay with Rollbar to reproduce bugs and move faster.

  • Travel Syndication Technology (TST) — travel booking engine — used search and session replay to identify errors in their booking process.

  • Clubhouse — project management app — after spending months trying to reproduce bugs, session replay was able to reproduce the problem in minutes.

Paying engineers to reproduce bugs gets expensive quickly, which makes tools that speed up the process invaluable. Session replay is a powerful analytics tool to reduce dramatically the time it takes to understand and eliminate software glitches, coding errors, and other pesky bugs on websites and web applications.

Before FullStory, we had no idea how long it might take to locate an issue. Now, we know it will only take as long as the customer's session took. — Jerry Hoopfer, Project Manager, Moosejaw

Learn more about using session replay to solve bugs fast →

2 | Conversion rate optimization

Whether in ecommerce, marketing, or product development, optimizing conversions for your website or app is an ongoing, never-ending process.

Here are just a few problems optimizers face:

» I need to understand what is preventing users from converting (or triggering some KPI).

» What’s not working about my landing page?

» Why are users missing my CTA?

» Where are my customers losing interest?

Session replay tools help conversion rate optimization by showing what is happening on a given page or screen on your website or app. This level of detail helps you tease out why users are—or aren’t—converting.

For example, are users getting confused with your UI? Are they missing the CTA? Running into errors? Looking for missing information? And on and on. From these observations, hypotheses can be formed and tests run. Mix session replay with A/B tests and you can get more out of experiments and further optimize experiences.

How to use session replay for conversion rate optimization

UserConversion, a U.K. digital agency, shared how they use session replay to optimize conversions for clients. Take a deep dive into their strategy, including a guide, case-study in which they drove a 26% increase in conversion, webinar, and template for collection of observations.

Some session replay vendors also bring together search, replay, and funnel analytics so you can conduct aggregated analysis and qualitatively analyze real user behavior at each step of the funnel.

Below are examples of how session replay was used to drive conversion rate optimization (CRO):

  • SpanishDict — translation service — how a banner ad was pushing a core feature of the product off the page on mobile.

  • Zenstores — ecommerce platform — uses session replay to optimize the funnel.

  • Fullstack Digital — marketing agency — took conversion rates from 0-12% for a finance client.

  • Metromile — car insurance — using A/B testing on packages using an integration with Optimizely.

While CRO can often be seen as the job of marketers, optimization can involve everything from driving sales to feature adoption.

We believe that session recordings are one of the best conversion research techniques out there. Replay is natural user behavior that's not skewed by tasks or any kind of bias. — David Mannheim, Founder, User Conversion

Learn more about using session replay for conversion optimization →

3 | Support customers faster through context

Support professionals have an exceptionally challenging job. Helping customers who run into problems during their online experience can be an exercise in futility. Here are a few of the problems support professionals face:

» How do I get the context necessary to understand the customer's problem or need?

» "Could you provide a screenshot?"

» How do I answer a ticket that says, "It's not working" quickly and effectively—without further frustrating the customer?

Integrate FullStory with help desk solutions

With session replay tools you can match customer support tickets and customer service questions to session links. Learn how FullStory integrates with Intercom, Zendesk, Trello, Slack, etc.

Bellow are examples of how session replay is used to help support professionals get the context they need to help customers faster.

  • Zenstores — ecommerce platform — resolve customer support inquiries in half the time.

  • FinTech company — financial technology — increased one-touch resolutions by 57%.

  • TravelPerk — travel booking platform — connects support tickets to customer support agent, product owner, and designer to find the source of an issue within moments.

  • Travel Syndication Technology — travel booking platform — going from screenshots to session replay a "game changer."

  • — not-for-profit — used with Zendesk, solved why users were accidentally double-donating and requesting refunds.

Additionally, some session replay tools can be used to "go live," and co-browse with users at low-latency (1–5 second delay) so that support agents can help in real-time navigate through site or UI problems (More on co-browsing here and here).

Our primary support channels are email, phone, and in-app chat, all of which are limited by the user's ability to explain the problem. Ideally, we'd want to be in the same room as the customer, seeing what they're seeing. FullStory makes that possible. — Alex Myers, Marketing, Zenstores

Learn more about using session replay for support →

4 | Understand the user experience (UX)

It's almost impossible to understand how digital products are used without directly observing users. But designers, developers, and other stakeholders in the user experience must make these observations in order to improve the product. Here are a few of the problems faced and questions asked when trying to understand UX:

» Is my design working? Does it make sense to users?

» How do I understand the UX across the thousands of devices, browsers, screen resolutions, OS, etc.?

» UX research studies are costly, slow, and unreliable—but what other choice is there?

Session replay is a useful tool for gathering user experience research on-demand and “at scale” to help designers see where elements are not understood or how different devices, screen resolutions, and browsers are presenting an experience to users.

Below are examples of how session replay is used to help UX designers understand how their website or app is used:

  • Prospero — proposal creation app — see how design doesn't work in certain computer resolutions, or how users bounce because they can't find a button.

  • Aweber — email marketing — understanding how users find the mobile experience lacks certain desired features that exist on desktop.

  • SpanishDict — translation service — understand how the mobile experience is breaking due to banner ads pushing core functionality off the mobile web page.

  • Tray — cloud services connector — discovers how users are confused in creating connections resulting in creation of better discoverability around deleting connections.

Two special cases for understanding UX are explained in #5 — Onboarding#6 Feature adoption, and #7 Dynamic states below.

5 | Understand and improve onboarding [UX]

Another way session replay can be used to understand UX is by watching sessions of users who go through onboarding flows to understand where users miss things, lose interest, or fail to understand functionality.

Below are examples of how users understand onboarding using session replay:

  • Autopilot — multi-channel marketing automation software — boosted activations 15% by redesigning onboarding tutorial based on insights gathered from researching sessions.

  • Wistia —  online video platform — improved onboarding resulting in a saw a 30% increase in their customization engagement metric.

  • Help Scout —  help desk platform — streamlined the creation of new users on observing how users were getting confused.

  • Go Pollock  —  education app — noticed users weren't making it to the demo process because of friction in registration. Eliminated registration to streamline the process.

If you're into onboarding and session replay, be sure to bookmark these 5 tips for improving user onboarding with session replay.

6 | Measure and understand feature adoption [UX]

A specific way session replay is used to understand UX is to measure and analyze feature adoption. With session replay, you can observe and analyze user sessions that contain interactions with a specific new product feature.

Additionally, if your session replay tool includes a way to identify individual visitors, you can use session replay to identify the set of users who engaged with the new feature (or the list of those who did not engage) for the purpose of following up appropriately, later (E.g. conduct surveys, interviews, etc.).

Read how Socialie (a social media app that connects brands to influencers) uses session replay to understand UX for feature adoption.

7 | See how users interact with dynamic web app states [UX]

Web analytics often fail to provide enough data to understand how users engage with dynamic web app states (E.g. pop-ups, lightbox, dropdown menus, endlessly scrolling pages, or whatever dynamic content lives on your site).

These dynamic states aren’t a problem for session replay.

Additionally, with a tool like FullStory’s Page Insights and Click Maps, you can see aggregated metrics against these dynamic app or page states (More on Click Maps here and here).

8. Understand marketing funnels — Session replay tools that provide for the ability to filter user sessions by multiple events or user actions can be used to analyze marketing funnels and optimize experiences by watching sessions of users that fall out of the funnel. See how Zenstores, an e-Commerce platform, used observations from session replay to understand and optimize landing page performance.

9. Analyze the effectiveness of online advertising — Using UTM parameters and referral sources, session replay can help marketing teams understand how users from different advertising campaigns are reacting to landing pages and other marketing collateral. Team members can watch sessions for specific signs of engagement.

You can also analyze recorded sessions from paid visits in which the user stays less than 5 seconds (for example) or longer than 30 seconds. Use resulting observations to optimize advertising sources by those that drive the highest quality traffic—and cutting sources that send a large number of bots, have an audience mismatch, or send otherwise low-relevance leads.

10. Discover and observe user frustration — Because a session replay tool captures all visitor interactions, it also picks up signals that indicate user frustration and customer struggle.

FullStory helps discover “Rage Clicks,” which are rapid-fire clicks on a specific element. Other frustration signals FullStory session replay tracks that suggest friction in the customer experience include Error Clicks, Dead Clicks, Thrashed Cursor, and Form Abandonment.

Sessions can be watched to determine what's not working well—or not working at all—for the purpose of optimizing conversions, improving the UX, etc. Read more on frustration signals in The guide to understanding frustration online.

11. Discover and watch sessions that include form abandonment — Similar to rage clicks, session replay tools such as FullStory have form analytics that find when users abandon a form on your web site or app. Watching sessions that include form abandonment can help discover if certain aspects of the form were dissuading completion—or if some problem is occurring as users navigate the form fields.

12. Detect suspicious activity — SQL injection attacks, URL attacks, and cross-site scripting (XSS) are methods malicious actors might use to hack your site. While not all session replay tools can detect and report on these activities, FullStory can. Searching for and watching sessions that include suspected suspicious activity can reveal if malicious actors are trying to affect your web site or app. More on suspicious activity detection here.

13. Measure how page load and site performance varies across different browsers and devices — Ever wonder about performance on different browsers? Cut your sessions by device and browser variables and observe how good—or bad—your site performance is by device and browser.

14. Legal evidence, fraud protection — Because user session recording captures everything the user sees, it can be used to prove that a user saw or did something specific. (This can be useful for preventing fraud.)

15. Customer journey mapping — What better way to see how a visitor journeys through your website than by researching the complete journey with session recording? Read more about customer journey mapping using session replay here.

Qualitative and quantitative, better together

Session replay is a powerful form of qualitative research, enabling researchers to see, subjectively, the behaviors of individual users.

From a research perspective, session replay deftly avoids bias in user testing—i.e. the Hawthorne Effect—because sessions are captured from actual users rather than test subjects in a study.

Additionally, unlike traditional qualitative research methods that require advance setup, can be challenging to execute, and are often prohibitively expensive, session replay tools on-demand. And can be used on any aspect of your online customer experience.

The qualitative meets the quantitative on FullStory

While session replay alone is useful from a qualitative research perspective, because session replay tools capture all user data, they present the opportunity to go a step further, connecting qualitative data to high-level, aggregated quantitative analysis.

For example, in FullStory you can search for sessions from new users and further filter that list of sessions for those engaged with a specific element or URL on your web site. The resulting segmented list of user sessions will include accompanying “intelligent data visualizations”—graphs and trend lines on data like traffic countsfunnels (if applicable), error clickstop users, and more.

FullStory also provides aggregated insights on user sessions by page and app state, deftly solving the problem of diversity in devices, browser sizes, and any number of modern states of web applications (E.g. dynamic overlays, dropdown menus, endlessly scrolling pages, etc.). See more on this capability in Page Insights with Click Maps.

FullStory connects the qualitative to the quantitative

Session replay on FullStory builds aggregated web analytics from the ground-up. High-level analysis can be run based on whatever user interaction makes sense. You're no longer limited to a handful of high-level, aggregated metrics provided by the tool (E.g. sessions, users, page visits, bounce rates, etc.).

Job functions that benefit from session replay

If your work touches the customer experience online, session replay is for you. Some of common job roles that use FullStory include product managers, product developers, engineers, designers, UX researchers, customer support, and marketing teams.

Product Management, development, and engineering

Session replay is a useful tool for product managers, product developers, and engineers. As explained above, session replay works as a debugging tool as bug reproduction is as simple as finding sessions that contain errors and watching the playback. Meanwhile, if your session replay tool has the capacity to search sessions for events, sessions containing errors can be found through search.

Additionally, when integrated with customer support tools, bug reports from users can be attached to session recordings, eliminating the need to reproduce the bug through trial and error, and saving engineers the time spent decoding user-written bug reports.

Design and user experience (UX) research

Designers understand that even the most elegant, thoughtful site or app design is likely to have unexpected user behaviors once launched. Variations in devices, browsers, and the page and app state can affect design elements. Users can be confused by elements that the design team thought were obvious or intuitive.

Understanding the user experience around design can be as simple as watching sessions, observing behavior and user interactions with the design, experimenting, and iterating on the design further.

Customer support

Session replay has become a must-have customer support tool for professionals. Why? Playback gives support agents important context around solving customer support tickets—it even allowing for customer support teams to co-browse with users “live.”

Given the challenges of asynchronous communication and customer inability to articulate in a meaningful way a given web experience through a ticket (or on the phone), watching a session replay saves time, generates empathy in the support team, and results in better, more efficient outcomes. Additionally, the trail left by session replay allows customer support staff to “close the loop” with product managers when certain aspects of your web site or app continue to cause problems (e.g. see how to convince your product manager that a bug needs to get fixed).


Marketers measure ROI to track how well marketing and advertising campaigns drive specific behaviors including clicks, lead generation, conversions, and other KPIs. Unlike these abstract marketing metrics, session replay can help you optimize conversions by providing the necessary nuance of real user behaviors. It's that nuance that provides marketers with the answers they need to build better landing pages, run A/B tests, analyze results of experiments and more.

Additionally, if your session replay tool allows you to search and analyze segments of users by their behaviors or acquisition channel, you can accurately assess the quality of a given marketing tactic. For example, you can find and watch sessions of users who arrive on a landing page via Google paid search or Facebook Ads.

Another benefit of replay tools with segmentation is you can isolate a set of users—say your power users or users in a certain geography—and export lists for email marketing campaigns or other marketing strategies.

Tools like FullStory also provide the ability to build marketing funnels based on the combination of any number of user- or event-based search criteria.

5. Finding the right session replay vendor

Many session replay tool options exist. And due to the technical requirements "under the hood," not all playback tools are the same.

If you're tasked with finding the best replay tool for your organization, arm yourself with the research to evaluate and find a replay tool that meets your needs. To that end, below you'll find a list of the top session replay vendors/tools, the key criteria to consider in reviewing a given tool, and how FullStory session replay meets or exceeds these criteria.

The top session replay solutions (vendors)

Below is a list of the top session replay solutions:

10 criteria for evaluating session replay vendors

Below are 10 criteria to consider when evaluating any given session replay tool. Each of these considerations should be weighted against a given tool's technical capabilities and features. (You can skip to how FullStory stacks up here.)

1. Search, segmenting, or filtering sessions

Now that you have thousands of user sessions, how do you find specific sessions?

Finding the specific session or set of user sessions that meet given criteria is necessary to get to the “why?” session replay provides. Not all vendors allow you to search or filter and segment sessions by events.

2. Language and code capabilities

Session replay tools record what happens in the DOM. Different session replay tools can capture more (or less) than others as web and app elements vary in their complexity. If your site has a particularly nuanced or complicated setup, it’s worth checking to make sure the session replay tool you’re researching will work.

3. Single-page apps

“Will session replay work with my REACT site? What about Angular.js? Does session replay work with [INSERT JAVASCRIPT FRAMEWORK HERE]? Are there any caveats? Does it work out of the box or is someone going to have to code things into my page or onto the vendor's backend?"

4. Performance

Session replay tools necessarily use proprietary code to capture data from your site or app. The technology and implementation can affect the speed of your site.

5. Asset caching

Does the session replay tool cache assets to ensure playback fidelity in the event the site changes?

Not all session replay tools save the associated assets (e.g. images, CSS, HTML, and many other materials used to build web pages and apps). For session replay tools that do not cache assets, in the event the web site and app changes, session recordings are likely to lose their utility.

6. Data retention

Session replay vendors must store lots of data, so how many days, weeks, or months of sessions that are retained by a given tool will vary.

7. Sessions recorded (sampling vs. everything)

Some tools only capture a sampling of sessions while others—like FullStory—capture them all. Sampling limits the ability to dive into customer support tickets by user session (or co-browse), assign sessions to bug reports, generate aggregated insights, gather insights on edge-cases, as well as other limitations.

8. Ability to identify specific sessions by user

Related to differences in sampling vs. capturing all sessions, some session replay tools allow you to identify sessions by users.

9. Implementation

Depending on the tool, implementing the necessary script and/or code to make session replay work on your site can vary in complexity. Some tools take months of implementation or nuanced installation requirements.

10. Price

Session replay vendors can vary in price depending on variables like data retention, sessions covered, additional features, and more.

See the FullStory difference

FullStory's powerful platform gives you the power to know your customer's digital experience. And when it comes to session replay, FullStory is best-in-class. Here's how FullStory measures up against the 10 criteria for evaluation below.

Search, segment, and filter

☞ FullStory indexes all user sessions and can be searched for events, users, date & time constraints, clicked elements, URLs, time, location, CSS selectors, and countless other web elements, all of which can be stacked to allow for highly specific segmentation of users based on behavior.

Language and code capabilities

☞ We record everything mentioned in Session Recording Capabilities and are actively working to expand our session recording capabilities.

Single-page apps

☞ The answer will vary by session replay tool, with FullStory, the answer is usually, “Yes,” without caveats or reservations.


☞ FullStory has gone to great lengths and made use of multiple tactics to make the session recording script as lightweight as possible (More on this here). As a result, the FullStory script will not affect the performance of your site.

Asset caching

☞ FullStory caches assets so historical sessions that are retained by customers are protected from future web page and app changes.

Data retention

☞ FullStory plans can meet whatever data retention required.

Sampling vs. everything

☞ FullStory captures every session where the script is installed. No sampling means no bug goes uncaptured, no niche experience missed, and every support ticket can be tied to a specific customer experience.

Ability to identify sessions by user

☞ FullStory allows users to identify sessions by users (See FS.identify).


☞ Installing FullStory starts with placing a small snippet in the head of your site to begin recording. As part of the implementation, you can exclude specific fields, send over custom data, and integrate FullStory with other tools in your stack.


☞ FullStory offers custom plans for businesses based on their needs. Basic capabilities are available on the Free plan. Contact us to learn more.

6. Seeing is believing

Isn't it time you got to the bottom of your customer's digital experience?

Give FullStory and session replay a try. Your free trial of FullStory Pro includes our industry-leading searchable session replay, Click maps and heatmaps, bug squashing and performance optimizing Dev Tools, setup-free frustration signals, and more.

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Last updated, October 2019. Problem with this guide? Email us.