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    Overview
    ProductRatingMost Used ByProduct SummaryStarting Price

    Google Tag Manager

    Score9.5 out of 10
    N/AFrom Google, the Google Tag Manager is a tag management application that facilitates creating, embedding, and updating tags across websites and mobile apps. It is a free option, vs. the company's enterprise-tier Google Tag Manager 360.

    $0

    Optimizely Web Experimentation

    Score8.7 out of 10
    N/AWhether launching a first test or scaling a sophisticated experimentation program, Optimizely Web Experimentation aims to deliver the insights needed to craft high-performing digital experiences that drive engagement, increase conversions, and accelerate growth.N/A
    Pricing
    Google Tag ManagerOptimizely Web Experimentation
    Editions & Modules
    No answers on this topic
    No answers on this topic
    Offerings
    Pricing Offerings
    Google Tag ManagerOptimizely Web Experimentation
    Free Trial
    NoYes
    Free/Freemium Version
    YesNo
    Premium Consulting/Integration Services
    NoYes
    Entry-level Setup FeeNo setup feeOptional
    Additional Details——
    More Pricing Information
    Community Pulse
    Google Tag ManagerOptimizely Web Experimentation
    Considered Both Products
    Google
    Chose Google Tag Manager
    As I said before, GA4 doesn’t allow for much custom tracking so using Google Tag Manager to fill the gaps makes sense. There are many tools available to track conversions and user actions but the most sensible option for us was to go with Google Tag Manager as most of our …
    Incentivized
    Chose Google Tag Manager
    Google Tag Manager is the only tag management tool I have used.
    Incentivized
    Optimizely
    Chose Optimizely Web Experimentation
    We haven't used other Optimizely products apart from Web Experimentation.
    Incentivized
    Chose Optimizely Web Experimentation
    Google Optimize was much less flexible for our program needs and requires Google Analytics for analysis and metrics tracking. Optimizely Web Experimentation lets you build any number of metrics which can be much more complex than standard GA goals. Optimizely Web …
    Incentivized
    Chose Optimizely Web Experimentation
    It is pretty good in comparison. The biggest difference is the metrics dashboard for experiments which gives us granular data related to the experiment being run. I think honestly there is a lot right now my company is probably not utilizing when it comes to optimizely but I do …
    Incentivized
    Chose Optimizely Web Experimentation
    Optimizely has better customer service if you need to talk to a person and a great library of documentation if you run into issues and want to troubleshoot yourself. Web Experimentation has allowed for our testing capabilities to grow as our research program develops. …
    Incentivized
    Chose Optimizely Web Experimentation
    We prefer Optimizely for ease of use and more functionality, but it's currently become too expensive for our non-profit organization, and we are switching to Google Optimize going forward.
    Incentivized
    Key User Insights
    Would buy again
    93%
    Would buy again
    14 Answers
    95%
    Would buy again
    89 Answers
    Delivers good value for the price
    100%
    Delivers good value for the price
    14 Answers
    96%
    Delivers good value for the price
    69 Answers
    Happy with the feature set
    100%
    Happy with the feature set
    15 Answers
    95%
    Happy with the feature set
    89 Answers
    Lived up to sales and marketing promises
    100%
    Lived up to sales and marketing promises
    11 Answers
    91%
    Lived up to sales and marketing promises
    52 Answers
    Implementation went as expected
    93%
    Implementation went as expected
    13 Answers
    87%
    Implementation went as expected
    58 Answers
    Features
    Google Tag ManagerOptimizely Web Experimentation
    Security
    Comparison of Security features of Google Tag Manager and Optimizely Web Experimentation
    Feature
    Google Tag Manager
    8.9
    58 Ratings
    5% above category average
    Optimizely Web Experimentation
    -
    Ratings
    Role-based user permissions8.958 Ratings00 Ratings
    Tag Management
    Comparison of Tag Management features of Google Tag Manager and Optimizely Web Experimentation
    Feature
    Google Tag Manager
    8.8
    68 Ratings
    8% above category average
    Optimizely Web Experimentation
    -
    Ratings
    Tag library9.263 Ratings00 Ratings
    Tag variable mapping8.955 Ratings00 Ratings
    Ease of writing custom tags7.367 Ratings00 Ratings
    Rules-driven tag execution8.162 Ratings00 Ratings
    Tag performance monitoring10.056 Ratings00 Ratings
    Page load times8.849 Ratings00 Ratings
    Mobile app tagging9.334 Ratings00 Ratings
    Library of JavaScript extensions8.838 Ratings00 Ratings
    Data Management & Integrity
    Comparison of Data Management & Integrity features of Google Tag Manager and Optimizely Web Experimentation
    Feature
    Google Tag Manager
    7.6
    69 Ratings
    7% below category average
    Optimizely Web Experimentation
    -
    Ratings
    Event tracking8.666 Ratings00 Ratings
    Mobile event tracking9.347 Ratings00 Ratings
    Data distribution management8.841 Ratings00 Ratings
    Universal data layer8.358 Ratings00 Ratings
    Automated error checking3.045 Ratings00 Ratings
    Testing and Experimentation
    Comparison of Testing and Experimentation features of Google Tag Manager and Optimizely Web Experimentation
    Feature
    Google Tag Manager
    -
    Ratings
    Optimizely Web Experimentation
    8.0
    163 Ratings
    5% below category average
    a/b experiment testing00 Ratings9.0163 Ratings
    Split URL testing00 Ratings8.5135 Ratings
    Multivariate testing00 Ratings8.4139 Ratings
    Multi-page/funnel testing00 Ratings7.9126 Ratings
    Cross-browser testing00 Ratings8.197 Ratings
    Mobile app testing00 Ratings8.075 Ratings
    Test significance00 Ratings8.4147 Ratings
    Visual / WYSIWYG editor00 Ratings8.1133 Ratings
    Advanced code editor00 Ratings7.9125 Ratings
    Page surveys00 Ratings6.217 Ratings
    Visitor recordings00 Ratings8.418 Ratings
    Preview mode00 Ratings7.6145 Ratings
    Test duration calculator00 Ratings7.9112 Ratings
    Experiment scheduler00 Ratings8.2112 Ratings
    Experiment workflow and approval00 Ratings7.890 Ratings
    Dynamic experiment activation00 Ratings7.574 Ratings
    Client-side tests00 Ratings7.896 Ratings
    Server-side tests00 Ratings7.250 Ratings
    Mutually exclusive tests00 Ratings8.280 Ratings
    Audience Segmentation & Targeting
    Comparison of Audience Segmentation & Targeting features of Google Tag Manager and Optimizely Web Experimentation
    Feature
    Google Tag Manager
    -
    Ratings
    Optimizely Web Experimentation
    8.2
    152 Ratings
    7% below category average
    Standard visitor segmentation00 Ratings8.4147 Ratings
    Behavioral visitor segmentation00 Ratings7.6122 Ratings
    Traffic allocation control00 Ratings9.1144 Ratings
    Website personalization00 Ratings7.8111 Ratings
    Results and Analysis
    Comparison of Results and Analysis features of Google Tag Manager and Optimizely Web Experimentation
    Feature
    Google Tag Manager
    -
    Ratings
    Optimizely Web Experimentation
    8.3
    149 Ratings
    4% below category average
    Heatmap tool00 Ratings9.313 Ratings
    Click analytics00 Ratings8.833 Ratings
    Scroll maps00 Ratings8.517 Ratings
    Form fill analysis00 Ratings8.072 Ratings
    Conversion tracking00 Ratings8.744 Ratings
    Goal tracking00 Ratings8.2127 Ratings
    Test reporting00 Ratings7.9137 Ratings
    Results segmentation00 Ratings7.7103 Ratings
    CSV export00 Ratings7.9102 Ratings
    Experiments results dashboard00 Ratings8.049 Ratings
    Best Alternatives
    Google Tag ManagerOptimizely Web Experimentation
    Small Businesses
    Adobe Experience Platform Launch
    Score8.4 out of 10
    Google Optimize
    Score6.7 out of 10
    Medium-sized Companies
    Adobe Experience Platform Launch
    Score8.4 out of 10
    AB Tasty
    Score8.6 out of 10
    Enterprises
    Adobe Dynamic Tag Management (discontinued)
    Score10 out of 10
    Google Content Experiments (discontinued)
    Score7.3 out of 10
    All AlternativesView all alternativesView all alternatives
    User Ratings
    Google Tag ManagerOptimizely Web Experimentation
    Likelihood to Recommend
    9.7
    (73 ratings)
    8.7
    (254 ratings)
    Likelihood to Renew
    7.0
    (7 ratings)
    9.5
    (51 ratings)
    Usability
    7.1
    (18 ratings)
    10.0
    (58 ratings)
    Availability
    9.1
    (1 ratings)
    10.0
    (7 ratings)
    Performance
    -
    (0 ratings)
    7.3
    (6 ratings)
    Support Rating
    2.0
    (12 ratings)
    10.0
    (16 ratings)
    Online Training
    7.3
    (1 ratings)
    3.0
    (1 ratings)
    Implementation Rating
    9.8
    (2 ratings)
    8.0
    (11 ratings)
    Configurability
    -
    (0 ratings)
    6.0
    (1 ratings)
    Product Scalability
    -
    (0 ratings)
    8.0
    (163 ratings)
    User Testimonials
    Google Tag ManagerOptimizely Web Experimentation
    Likelihood to Recommend
    Google
    I have found Google Tag Manager as the go to solution for managing all of your event and conversion tags for your website. Not only does it make it easy to manage all of your tags in the one place, it is fairly intuitive to use and there is plenty of videos and help documentation online to help set up what ever you need. No scenarios come to mind at the moment on where it is less appropriate to use.
    Incentivized
    Read full review
    Optimizely
    I think it can serve the whole spectrum of experiences from people who are just getting used to web experimentation. It's really easy to pick up and use. If you're more experienced then it works well because it just gets out of the way and lets you really focus on the experimentation side of things. So yeah, strongly recommend. I think it is well suited both to small businesses and large enterprises as well. I think it's got a really low barrier to entry. It's very easy to integrate on your website and get results quickly. Likewise, if you are a big business, it's incrementally adoptable, so you can start out with one component of optimizing and you can build there and start to build in things like data CMS to augment experimentation as well. So it's got a really strong a pathway to grow your MarTech platform if you're a small company or a big company.
    Incentivized
    Read full review
    Pros
    Google
    • Selecting elements on a site [object, class, cookie, etc] (to later fire an event, send some data, etc) is very easy with triggers. Want to add an event when someone clicks on a button? Super easy. It was many many DOM selectors and you can even add custom functions if you need to do something more specific
    • In general, firing events in different circumstances is very easy mixing triggers and tags. You can track almost any element of the DOM and do whatever you want with it.
    • Testing is a great functionality. Only you can see what's on the site and you can debug it easily by seeing which events or tags were triggered and all the DOM elements involved (and why they matched the trigger).
    • Working in environments (staging, production) and versioning is easy to do, deploying changes in 2 clicks.
    Incentivized
    Read full review
    Optimizely
    • The Platform contains drag-and-drop editor options for creating variations, which ease the A/B tests process, as it does not require any coding or development resources.
    • Establishing it is so simple that even a non-technical person can do it perfectly.
    • It provides real-time results and analytics with robust dashboard access through which you can quickly analyze how different variations perform. With this, your team can easily make data-driven decisions Fastly.
    Incentivized
    Read full review
    Cons
    Google
    • There are several good integrations, but there can always be more. Native tracking for call tracking solutions, analytics providers, non-Google advertisers would be top of my list.
    • Documentation is just dreadful. Luckily there are some awesome folks out there doing crowdsourced tutorials (shout out to Simo Ahava) but by and large the Google Tag Manager instructions are worth what you pay for them.
    Incentivized
    Read full review
    Optimizely
    • JavaScript is hard to implement sometimes especially for JQuery elements
    • ROI reporting should be part of the overall experimentation reporting
    • CMP integration: where we can easily show status of test on the HPT request
    • CMS integration
    • More widgets like social proof banners, etc.
    Incentivized
    Read full review
    Likelihood to Renew
    Google
    I haven't found another option for us to use especially one that is free. Down the road we may go a different route but for now GTM is a good option and does what we need it to do. It'd be nice to get more support or more integrations but with the free version there's only so much one can expect to get I suppose.
    Incentivized
    Read full review
    Optimizely
    I rated this question because at this stage, Optimizely does most everything we need so I don't foresee a need to migrate to a new tool. We have the infrastructure already in place and it is a sizeable lift to pivot to another tool with no guarantee that it will work as good or even better than Optimizely
    Incentivized
    Read full review
    Usability
    Google
    No difficult obstacle to overcome but Google Tag Manager can still be difficult for many users to deploy. Sure the basic HTML script can be deployed quite easily, but when you start to require triggers, variables, etc, it can be a little daunting.
    Incentivized
    Read full review
    Optimizely
    Optimizely Web Experimentation's visual editor is handy for non-technical or quick iterative testing. When it comes to content changes it's as easy as going into wordpress, clicking around, and then seeing your changes live--what you see is what you get. The preview and approval process for sharing built experiments is also handy for sharing experiments across teams for QA purposes or otherwise.
    Incentivized
    Read full review
    Reliability and Availability
    Google
    No answers on this topic
    Optimizely
    I would rate Optimizely Web Experimentation's availability as a 10 out of 10. The software is reliable and does not experience any application errors or unplanned outages. Additionally, the customer service and technical support teams are always available to help with any issues or questions.
    Incentivized
    Read full review
    Performance
    Google
    No answers on this topic
    Optimizely
    I would rate Optimizely Web Experimentation's performance as a 9 out of 10. Pages load quickly, reports are complete in a reasonable time frame, and the software does not slow down any other software or systems that it integrates with. Additionally, the customer service and technical support teams are always available to help with any issues or questions.
    Incentivized
    Read full review
    Support Rating
    Google
    GTM does not provide support. This is one of GTM's biggest issues but it's due to the level of customization for each website. If your team thinks they would heavily rely on the need for a support staff it is probably better to invest in a paid service with a team that can support your needs.
    Incentivized
    Read full review
    Optimizely
    They always are quick to respond, and are so friendly and helpful. They always answer the phone right away. And [they are] always willing to not only help you with your problem, but if you need ideas they have suggestions as well.
    Read full review
    Online Training
    Google
    I thought there was a little bit too much emphasis on AdWords stuff, not enough on the generic application of GTM.
    Read full review
    Optimizely
    The tool itself is not very difficult to use so training was not very useful in my opinion. It did not also account for success events more complex than a click (which my company being ecommerce is looking to examine more than a mere click).
    Read full review
    Implementation Rating
    Google
    Planning and communication will help greatly with an in-house implementation. If there are large teams, try to limit the number of people involved to 1-2 developers (back-end dev may be necessary depending on your platform), one analytics marketer and one project manager.
    Incentivized
    Read full review
    Optimizely
    In retrospect: - I think I should have stressed more demo's / workshopping with the Optimizely team at the start. I felt too confident during demo stages, and when came time to actually start, I was a bit lost. (The answer is likely I should have had them on-hand for our first install.. they offered but I thought I was OK.) - Really getting an understanding / asking them prior to install of how to make it really work for checkout pages / one that uses dynamic content or user interaction to determine what the UI does. Could have saved some time by addressing this at the beginning, as some things we needed to create on our site for Optimizely to "use" as a trigger for the variation test. - Having a number of planned/hoped-for tests already in-hand before working with Optimizely team. Sharing those thoughts with them would likely have started conversations on additional things we needed to do to make them work (rather than figuring that out during the actual builds). Since I had development time available, I could have added more things to the baseline installation since my developers were already "looking under the hood" of the site.
    Read full review
    Alternatives Considered
    Google
    We moved to GTM from a standard Google Analytics implementation. GTM is much more flexible and easier to make changes, especially as the changes relate to multiple sites and environments. While there is a learning curve when figuring out how to use GTM, I believe the change has been worth it because it helps us understand at a more fundamental level how our tracking works and gives us a lot more control over what we track and how.
    Incentivized
    Read full review
    Optimizely
    The ability to do A/B testing in Optimizely along with the associated statistical modelling and audience segmentation means it is a much better solution than using something like Google Analytics were a lot more effort is required to identify and isolate the specific data you need to confidently make changes
    Incentivized
    Read full review
    Scalability
    Google
    No answers on this topic
    Optimizely
    We can use it flexibly across lines of business and have it in use across two departments. We have different use cases and slightly different outcomes, but can unify our results based on impact to the bottom line. Finally, we can generate value from anywhere in the org for any stakeholders as needed.
    Incentivized
    Read full review
    Return on Investment
    Google
    • GTM is very useful to determine if a particular element on the site is useful (i.e. is it being watched, is it being clicked, does it help customers navigate through more pages). As an SEO person, I can use this information to decide what to optimize for but also to track progress and see improvements in engagement.
    • With the use of Google Tag Manager, I was able to easily inject an A/B testing tool which lead to several improvements in lead generation.
    Incentivized
    Read full review
    Optimizely
    • We're able to share definitive annualized revenue projections with our team, showing what would happen if we put a test into Production
    • Showing the results of a test on a new page or feature prior to full implementation on a site saves developer time (if a test proves the new element doesn't deliver a significant improvement.
    • Making a change via the WYSIWYG interface allows us to see multiple changes without developer intervention.
    Incentivized
    Read full review
    ScreenShots

    Optimizely Web Experimentation Screenshots

    Screenshot of AI-Powered Experimentation with Opal:

- Instant Test Ideas: Generates high-quality A/B test ideas based on any goals and audience insights.
- Smarter Experimentation: The AI can suggest impactful variations, reducing guesswork and increasing test velocity.
- More Than Just Ideas: From hypothesis generation to analyzing results, Opal helps optimize every stage of the experimentation process.Screenshot of the new Visual Editor with an AI Variation Development Agent

Create simple or advanced website changes fast without writing a line of code with our AI Development Agent.

Use natural language to build out your ideas and apply brand styles to your experiments instantly.Screenshot of Advanced Audience Targeting:

- Delivers personalized experiences by targeting users based on behaviors, attributes, and real-time conditions.
- Defines precise audience segments using first-party data, geolocation, and device type.
- Can test and optimize for different audience groups to maximize impact and engagement.Screenshot of Variation Template

Library of experience templates that you can access right within the Visual Editor. Customize these templates or create your own to easily reuse throughout your experimentation program.

- Offers pre-built templates for common test setups.
- Standardized variations and maintains brand integrity with reusable templates.
- Templates can be customized visually or tweak them with code for full flexibility.Screenshot of Web Experimentation Results Page:

- Data visualizations help interpret experiment performance.
- Displays which variations are winning with built-in statistical significance calculations.
- Results can be filtered by audience segments, events, and conversions to uncover key trends.Screenshot of the custom code editor for JavaScript & CSS changes, used to build complex tests.