What Is a Tag Manager? Differences Between GTM and YTM & Why You Should Implement One
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Category: Web Analytics, Privacy & Measurement Infrastructure
Authors: Shusaku Yosa
Published:
Last Updated:
Category: Web Analytics, Privacy & Measurement Infrastructure
Authors: Shusaku Yosa
When running web analytics and advertising campaigns, you need to place various "tags" on your site—GA4 tracking code, Google Ads conversion tags, Meta Ads pixels, and more. A "tag manager" is the tool that lets you centrally manage all these tags efficiently. This article explains the basic mechanics of tag managers, why you should implement one, and the key differences between the two most well-known tag managers: GTM (Google Tag Manager) and YTM (Yahoo! Tag Manager).
A tag manager is a tool that allows you to centrally manage and deploy the various tracking and advertising tags placed on your website from a single management interface. It is also referred to as a "tag management tool."
Normally, placing tags such as GA4, Google Ads, or Meta Ads on a website requires directly editing each page's HTML source code. As a site grows larger, the number of tags to manage increases, and it is not uncommon to need to request an engineer every time a tag is added or changed. By implementing a tag manager, you only need to place one "container tag" on your site, and then you can add, edit, and delete tags through the management interface without writing any code.
The mechanism behind a tag manager is simple. First, you place the tag manager's container snippet on every page of your site. Then, in the management interface, you configure which tags should fire on which pages and at which timing. When a page loads, the container snippet communicates with the tag manager's server and dynamically loads each tag based on your settings. This lets you control tag deployment entirely through the management interface, without ever editing your HTML source code.
Tag managers are indispensable tools for web managers and marketers. Here are five specific benefits you gain from implementation.
Without a tag manager, every time you add a new tag you must edit HTML source code, verify in a test environment, and then deploy to production. As the number of tags grows to 10 or 20, it becomes difficult to keep track of which tags are on which pages. With a tag manager, you can see all tags in one management interface, and adding, modifying, or removing tags takes just minutes.
A tag manager's interface can be operated without coding, so marketers and advertising managers can complete tag configurations on their own. There is no waiting for engineers or development teams when you want to add a new ad platform's tag or fix a conversion measurement tag. This speeds up execution and lets you run PDCA cycles faster.
When multiple tags are hard-coded in HTML, they may load synchronously and negatively impact page speed. Tag managers load tags asynchronously and in parallel, which can improve page load times. Furthermore, even if a particular tag errors out, it does not affect other tags, improving overall site stability.
GTM includes a Preview Mode (Tag Assistant) that lets you verify tag behavior before pushing changes to production. You can check which tags are firing, whether trigger conditions are working correctly, and whether variable values are as expected—all in real time. This helps prevent tracking gaps or double-counting caused by configuration mistakes.
In GTM, every time you publish a configuration, a version is automatically saved. If a new configuration has issues, you can revert to a previous version with one click. When multiple people manage the container, a full history of who changed what and when is preserved, providing peace of mind from a governance perspective.
The two most well-known tag managers in the Japanese market were GTM (Google Tag Manager) from Google and YTM (Yahoo! Tag Manager) from LY Corporation (formerly Yahoo Japan). Here we outline the features and differences of each.
GTM was released as a beta by Google in 2012 and officially launched in 2014. Anyone with a Google account can use it for free. It has extremely high compatibility with Google marketing tools like GA4 and Google Ads, with template tags that make setup easy. Through the Community Template Gallery, third-party tag templates such as Meta Pixel, LinkedIn Insight Tag, and Pinterest Tag are also widely available. Its robust operational features include Preview Mode (Tag Assistant) for advanced debugging, version control, and workspace functionality for parallel work among multiple team members. Because of its massive user base, there is an abundance of tutorials and documentation available in many languages.
YTM was a tag manager provided by LY Corporation (formerly Yahoo Japan), developed based on technology from US-based Signal. It was free to use for Yahoo! Ads (search ads and display ads) advertisers and supported tag templates from over 200 major domestic and international vendors. By placing a single "Yahoo! JAPAN Universal Tag" on a site, tag deployment could be controlled from the management interface. Its simple and intuitive interface, along with seamless integration with Yahoo! Ads, made it popular especially among major advertising agencies.
There were several important differences between the two. Regarding usage requirements, GTM was free for anyone with a Google account, while YTM required a Yahoo! Ads account. In terms of supported tag count, YTM appeared to have more with 200+ types, but GTM could effectively support any tag through Custom HTML tags. For debugging, GTM's Tag Assistant was extremely powerful, allowing real-time confirmation of tag firing status, trigger evaluation results, and variable values. YTM also had a preview function, but it lacked the detailed inspection capabilities of GTM. Additionally, GTM offered version control and workspace features, while YTM did not, making GTM superior for multi-person operations and rollbacks.
Here is the most important point: YTM (Yahoo! Tag Manager) was discontinued as of June 30, 2024. LY Corporation has not provided any replacement, and YTM users were required to migrate to other tag management tools.
The discontinuation was attributed to changes in LY Corporation's data strategy for marketing solutions and shifts in the usage of their one-tag solution. Since July 2024, access to the YTM management interface has been disabled and all tracking via the Universal Tag has been fully stopped. If the YTM Universal Tag remains on your site, it may cause page speed degradation or unexpected issues, so immediate removal is recommended if it is still present.
With the end of YTM, GTM (Google Tag Manager) has become the de facto industry standard for anyone looking to implement a tag manager today. GTM can manage Yahoo! Ads tags without any issues, making it the most recommended migration destination from YTM as well.
For those considering implementing a tag manager, here is a basic guide to setting up GTM.
First, log in with your Google account at the GTM official site (tagmanager.google.com) and create an account and container. A container is like a box that manages your tags—typically you create one container per website. Once a container is created, two code snippets are generated. The first should be placed as high as possible within the head element, and the second immediately after the opening body tag. If you use a CMS like WordPress, you can place them on all pages at once using the theme's header.php file or a plugin.
Once the container snippet is installed, you configure tags, triggers, and variables from the GTM management interface. For example, to start GA4 basic tracking, simply select the "Google Tag" template, enter your GA4 Measurement ID, and assign the "All Pages" trigger. After configuration, verify the setup in Preview Mode, and if everything works correctly, click "Publish" to push it to production.
With YTM's discontinuation, GTM is effectively the only free tag manager available. However, some enterprises may consider paid tag management solutions such as Adobe Experience Platform Launch (formerly Adobe DTM) or Tealium iQ. Key factors to consider include compatibility with your advertising platforms and tools, the robustness of debugging features, availability of permission management and version control for team operations, server-side tagging support, and cost.
For most small and medium-sized businesses and startups, GTM is the optimal choice—it is free, tightly integrated with the Google ecosystem, and backed by abundant documentation. For large-scale enterprise environments or advanced privacy requirements, paid tools may also be worth evaluating.
A tag manager is a tool for centrally managing the tracking and advertising tags placed on your website. Implementation dramatically reduces tag operational overhead, decreases dependence on engineers, improves page load speed, enables safe testing through preview features, and provides reliable operations through version control.
GTM (Google Tag Manager) and YTM (Yahoo! Tag Manager) were once the two dominant tag managers in the Japanese market, but YTM was discontinued in June 2024. Today, GTM is the industry standard for new tag manager implementations. If you have not yet implemented a tag manager, start by creating a GTM container.
To further leverage the tracking data accurately configured in GTM, you can combine it with a cross-media analytics tool like NeX-Ray to visualize and comparatively analyze advertising performance across multiple channels—Google Ads, Yahoo! Ads, Meta Ads, and more—all in one place. Build your data-driven marketing on a foundation of accurate tag configuration.
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