What is GTM?

Written by

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Aaron Vihersola

Co-founder

2 min reading time

Freelancer
Freelancer
Freelancer

GTM on Google Tag Manager – a tool that allows you to install and manage measurement tags without code changes. With it, you can effectively build GA4 events, conversion tracking, and marketing pixels.

What is GTM?

GTM (Google Tag Manager) is a tag management system. Through it, you can publish analytics and advertising scripts (GA4, Google Ads, Meta, LinkedIn, TikTok) without touching the website's code every time. Changes go into production via version control.

In short: GTM = central place for all tags + version history + preview.

What is GTM used for (basic set)

  • GA4 events: generate_lead, form_start, cta_click, click_call

  • Ad pixels: Google Ads, Meta, LinkedIn, TikTok, YouTube

  • Conversions and values: event values/currencies, dynamic parameters

  • Conditional triggers: only on certain pages, only once per session, etc.

7 steps to implementation

  1. Set up your container. Create a GTM container (web) and install two snippets on the site (head + body).

  2. Build layers. Create triggers (click, page view, form), tags (GA4/pixels) and variables (URL, CSS selector, dataLayer).

  3. Name clearly. E.g. GA4 – generate_lead (Form submit) or Ads – Conversion – Lead.

  4. Add parameters. Send GA4 things like value, currency, form_name, page_type.

  5. Preview and debug. Use Preview mode and check that the correct tag fires at the right moment.

  6. Publish the version. Add a description: what you changed and why. Revert to a previous version if necessary.

  7. Document. Keep a lightweight table: event, trigger, parameters, pages, owner.

Most common errors

  • Duplicates: the same conversion fires on a button and a thank-you page → CPA/CPL is distorted.

  • Wild trigger: pixel fires on all pages when it should only on specific ones.

  • Missing parameters: no value/currency → ROAS/POAS is obscured.

  • Untested publish: changes go directly to production without Preview.

  • No permissions/roles: anyone can change anything → chaos.

FAQ

Do I need GTM if I have GA4?
I strongly recommend it. You get events, conversions and pixels in one place and version control on top.

Can I install all pixels through GTM?
Most yes (Ads, Meta, LinkedIn, TikTok). Some have special cases (server-side, consent integrations), but web tags work directly.

How do I prevent duplicate conversions?
Trigger the conversion through one logic (e.g. thank-you page or button click, not both) and use a limit (once per event).

How do I measure phone clicks?
Trigger for links that start with tel: → send to GA4 with click_call parameters (e.g. link_text, page_path).

Do I need a dataLayer?
Often yes. It reliably passes product information, values, and state for events.

CTA

Do you want to ensure that GTM and GA4 are measuring correctly?
Order a measurement audit – we will fix duplicates, add missing parameters, and document the setup.

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